Millington, who was appointed on Saturday as Pete Wild's replacement, was set to speak to nearly all of his squad yesterday (Monday), with several of them out of contract this summer, including some key players such as captain Niall Maher, top-scorer Billy Waters and first-team regulars Tom Bradbury and Tyrell Warren.
Town could also face a battle trying to hold onto some players still under contract too. They have a year's option on youngsters Jesse Debrah and Kian Spence, but both will have attracted interest from elsewhere after impressive seasons.
When asked who was set to be staying or going, Millington said: "I don't know at the moment. It's a challenge, we're a club who, if players do well, it puts them on the radar of clubs with greater resources and some would argue greater status, and they'll take an interest in them.
"What we've got to do is express to the players, show them, demonstrate to them how much we value their input. We can do that in a number of ways.
"We've got to demonstrate to them exactly where their place is within the club and what they can gain from being here.
"We've got to make sure they understand they've got a future with us, and that when the time's right, and in some cases the time will come, that it's right for them to move on, either because they can't refuse the financial gain or because it's the right time to challenge themselves at a higher level.
"But I'd argue that in most cases, they can all stay and develop further with us over a period of time before they take that jump.
"There's always the risk with players that they move on a bit too soon, they move onto a club or a management structure where they're not going to get played in the position where they're best in, or they move onto a club as a development player rather than leaving us to go and play first-team football.
"We've seen it time and again, a player leaves to go and play under 23s football, then ends up out on loan and often gets forgotten about or dismissed if a new manager comes in.
"So there's arguments we can put to these players about the benefits of staying and we will work extremely hard to make them realise the benefits of staying with us for another season or more."
When asked how much of a challenge it would be to replace any of Town's star performers should they leave, Millington said: "You'll see when you look at clubs' retained and released lists that in a lot of cases, more players are released than retained, so there's certainly no shortage of footballers out there, and a lot of them are talented footballers.
"What you do find though is that certain players suit certain clubs at certain times.
"We recruit to a system and a style of play, so we want players who can fit into that quickly.
"The crucial element is the character because we've always worked very hard to have players of good character who want to come and work hard and contribute to the team. That's probably the hardest element to replace.
"What we know we've got amongst this group of players are some really good characters, some very good leaders, some very honest young men who are willing to work hard, willing to put their reputation and their careers on the line for the best interests of the club, and that's what we want, that's the most important aspect.
"So that is the hardest thing to replace, when that goes you've got to work incredibly hard to find players who are going to come in and do the same.
"That's why we want to retain as many of the players as we can, and we will work as hard as possible to do that."
Millington, who has been a popular figure among players in his three years at the club so far, does feel some within the squad may be more inclined to stay following the news of his appointment.
"I think so. The backroom staff are key to this because there are some players who will naturally get on with me more and some will naturally get on with the coach or the goalie coach or the physio," he said.
"These are relationships you want when you go into work every day.
"There are some players who will have friends among the playing staff who they want to stay with a bit longer.
"We know the players, we know what their development pathway has been over the past 12 or 24 months, and we know what we'd want their development pathway to be over the next 12 months, and we know we can help them continue on that.
"So I'm hoping some of those things will maybe add value to their decision, so where they have got the opportunity to move for more money or to that club with supposedly greater status, that might be counterbalanced by the fact there are a group of staff here who are well able, willing and available to help them continue on their development pathway and make them better players over the next 12 months."
On potential new signings coming into the club, Millington said: "We've got targets in every position. We always maintain a good list of targets for every position and in those positions, there'd be experienced Football League players, experienced National League players and young players who are coming through.
"So we've got extensive lists of targets who will fit into our playing style.
"We keep tabs on where they're up to, who's been released, who's possibly available for loans, and we try, with the help of Gareth McClelland, the head of recruitment, to have a clear grip on that.
"Knowing how many are going to come in from outside is difficult until we know exactly who we're going to be able to retain, but there's certainly targets there who we would be willing to go after if necessary.
"We want to deal with the boys we've got first of all, they're our priority, we want to make sure their situations are ironed out quickly, we want to come to a resolution with all of those as soon as possible.
"But there are players whose agents know we may trigger a conversation in the next seven days if we need to."
Millington will aim for a squad of between 20 and 22 players.
"We'll leave a bit of fat in the budget to be able to go out and strengthen," he said, "with the intention of doing that post-Christmas, but if necessary we'll look at doing that earlier if we feel we need to.
"It'll be run along very similar lines to the way it's been run over the last three seasons."
The new boss says the playing budget is expected to be at a similar level again next season.
"I know David's (Bosomworth) very keen for us to continue pushing towards the top end of the division, and so am I," he said.
"I'm ambitious for the team and I think there are key areas where we could maybe have done a it better this year.
"Although the budget initially will be in and around the same, I know that David will certainly be willing to have conversations and back us if we feel we need to strengthen in certain areas if we need to maintain or keep hold of a play-off push or better."
Halifax enjoyed a superb 2021-22 season, finishing higher than they ever had before as a new club, and with more points in the fifth tier than ever before since their reformation.
But Millington say there are lessons to be learned from the campaign too.
"Some of the performances where we dropped what looked like soft points are really crucial learnings for us," he said.
"I think we've got to be careful that our focus isn't an over focus on style over substance.
"Yes, we want to be attractive and we want to play football that entertains, we want people to come to The Shay knowing that they're going to see a good football team who moves the ball well, who has energy, who gets up the pitch, who creates chances. We want all of that to maintain a significant push for a title.
"At moments in games, we need to recognise when we need to sacrifice some of that style and have a bit more substance about us, and be a bit more rigid in our approach.
"I think that comes down to the management team. At times it's the management team who have to add that ten per cent, sometimes in a game things just need to be tightened up or changed slightly to maintain the possibility of pushing for a title."
Millington is far from daunted by the challenge of replicating or even improving on the season just gone though.
"I'm ambitious, I think it's only a number of weeks ago we had a very significant chance to win the league," he said.
"People forget we were in touching distance of Stockport, still with the game against them, and in all honesty, we let points slip at times.
"I'm really, really pleased with how the season panned out in terms of clean sheets, the points total is excellent, the home record, pushing teams like Wrexham, Stockport and Solihull as far as we did is something we should class as a good achievement.
"But we can be better, we could have been better. The points total could have been better, the league position could have been better, the play-off game could have been better.
"So why shouldn't we strive to improve those things? If it requires us getting more points or more clean sheets, if it requires us scoring more goals, then why shouldn't we aspire to that.
"I believe we've always got to be working to get better and I believe we've got the ability amongst the staff and this group of players to improve on what we've done this season."
Millington says his appointment means the journey will continue; evolution rather than revolution.
"Pete's done a fantastic job, and I've been a grateful passenger within that journey over the last three years," he said.
"But I'm probably a passenger who's contributed a reasonable amount.
"Although it was Pete's name above the door, I think what we achieved, he would quickly recognise, I've contributed to, the staff all contributed to, the players hugely contributed to, the people around the club influenced it, the fans influenced it in the way they supported us, especially in key moments.
"One man's gone, one important man who made some important decisions, has moved on, but there's an awful lot of people left who want to continue the journey and continue in a similar vein."
As well as speaking to his squad, high on Millington's to-do list is planning when pre-season training will begin.
"Me and Aaron (Scholes, physio) will be sitting down on Wednesday to go through dates," he said.
"Aaron's in the process of sorting out testing, so we've got some preliminary dates but we've got to work around availability for where we do the testing, which will then trigger the beginning of pre-season, but a normal time is a five-to-six week lead-in, which is what we'll be working towards."
Town's pre-season friendlies are also well on the way to being finalised.
"There's a number that Pete has organised over the past month or six weeks that he'd put in the diary, so we're just checking on the level of confirmation they've gone through," Millington said.
"There may need to be one or two supplementing that, just to stretch the squad in different ways.
"I'm hopeful we're not a million miles off being able to confirm those.
"In an ideal world we'd be looking for six, and we're not far off that."
Millington's appointment is his first management role in senior football, having previously worked at Altrincham's under 18s, Stockport County's academy with their under 16s, Macclesfield under 16s, Oldham under 16s, Hednesford, Curzon Ashton and Alfreton before teaming up with Pete Wild in the youth ranks at Oldham.
"My intention is to be the person I am, which is very reliant on making sure the processes and procedures are in place with how we work, so thorough planning, we deliver a performance or a session and then we review it and look to improve," the 46-year-old said.
"That's they key process that has underpinned our success so far and that's the way I'll continue.
"I've got some great relationships with the lads, I care dearly about them and I've got an affection for all of them. Within that relationship sometimes you need honesty, and I'm happy and willing to have honest conversations with them to help the team and move them forward.
"Not a huge amount will change about who I am and how I behave. Some of the roles and responsibilities I have will be slightly different, but the person that's stood in -front of the lads won't be a great deal different from the man that's stood in-front of them as the assistant manager."
Does Millington the manager mean a change in matchday attire?
"You may see me arrive in a suit if you're there early enough but in the technical area you'll see me in a tracksuit because that's how I like to be on the sideline," he said, "I want to be comfortable and able to do my job without any second thoughts."
When asked what his message to the Town fans was, Millington said: "Firstly a promise, that I'll give everything I've got to the team and to the club, I'll do everything within my power to improve what's already in place.
"Every decision and every effort I make will be with the club's best interests at heart.
"The only thing I ask in return is that they back the lads.
"I think they're fantastic on matchdays, when The Shay has a decent following, has the drum going and the crowd singing, I don't think there's any better place to watch your football.
"It's a fantastic place, so I'd ask them to turn up and keep doing what they do, which is back the lads and give them every support, safe in the knowledge that we go out and give it everything we can for the team."