I bought a couple of 15 year old regens recently that have a lot of potential. I want to know how best to make sure they reach their peak possibility. Should I send them out on loan to lesser teams for first team experience, or keep them in my youth academy (which has excellent facilities)?
There is no guarantee that you will be able to get a player to fulfil his potential. As you have bought them, there is the possibility that they won't settle at the club (especially if they are foreign and/or don't speak the same language). To counteract this, it is sometimes beneficial to
I'm pretty sure that you can't set out to actively offer players on loan until they are 17, and for sure you won't be able to play these players yourself until they are 16 so the U18 team (or whatever equivalent dependant on nation) is the best bet to continue their development. At 17 you then have a decision to make, it helps to check the reports of your coaches on the player to see what their current standard is (i.e. 'Player X would make a decent League 2 defender'). Again, this is entirely dependant on the league you are currently in, but if you feel you can afford the luxury of playing a weaker player in your team often (sub appearances when you're winning and easy cup games), then it is always best to keep the player in your squad. Don't forget, that even if you have him in the
Conversely, if you feel that you won't be able to give that player the playing time for whatever reason. You can offer him out on loan and it is possible that you will get offers for that player. Don't just accept every offer that comes in, you would do well to note where they want to play your player and if they would only be cover of a first team member. Sometimes it is better to loan a player to a worse team because they would be involved every week than loaning to a team where he will only make a handful of appearances. You can choose to send him out on loan for a short term loan, or a season long loan, obviously a season long loan would be more beneficial to a player but its always helpful to have the option to recall the player so you can always recall them from an unsuccessful loan spell, instead of risking a wasted season.
Again, dependant on your team and the ability of players in similar positions. You will need to decide again whether you would like to send him out on loan or to keep him in your squad, being sure to build on last season's progression. I.e. more appearances, upgrading his role in the squad (maybe rotation) or a loan at a better club.
Continuing this pattern will hopefully have given your player some very solid development and by 18/19 you should really be able to start reaping the benefits and full blood him into the first team and see how they fair. They'll either succeed or fail and you will have to be patient or move on. There are many things that can curtail his career, injuries, poor form, etc etc. There's no guarantee you will make a star out of him, and there are plenty more fish in the sea.