Sounds like a nice tip, but man do i hate releasing players and re-purchasing them, I like to keep a record of all of their caps and goals, assists... all that info under Manage Squad.
Totally agree! But when there is a juicy profit in line for you, you just get tempted to release the player & spend the profit on improving your team.
Last PES it was more frustrating because you had to keep releasing players when there form has gone down, because some players took a couple of days to return to good condition. You could always keep them, but it was pointless because they wouldn't be that effective.
P.S. Released Ronaldo & Messi AGAIN a few days ago. Made a combined 19 million profit from both, lol. Re-signed again straight away.