This is something that can surprise some newcomers to PES myClub. Getting the players/managers isn’t usually the hard part - keeping them is the real challenge.
Every 10 games, you will need to renew a player’s contract. A Black Ball player is more expensive than a Silver Ball, costing around 3-4k GP. This will be a problem, as this is roughly the same GP you make when you win a game, and if you’re rocking a 5-star team, you will need 35k every 10 games to keep using all your players.
You can also use coins to renew your players’ contracts, although I wouldn’t recommend it - you should save them for the weekly Featured Players/Teams or top Managers when you’re just starting out.
If you don’t renew the contract right away, you will still keep the player in your club - you simply won’t be able to play with him until the contract is renewed.
Every now and then you will also get some “Contract Renewal Tickets”. This basically means you can renew any player contract without spending GP/coins. Naturally, you should save those Tickets for your most expensive players.
Players' contract renewal become more expensive as they level up. If you're scouting for a player like Ronaldo, who probably will play often in your team, you can save some GP by immediately renewing his contract for dozens or hundreds of games while he is still level 1.
Managers are a little different: when their contract runs out, provided you have fulfilled their objectives, they will be extended for free.
If you failed to achieve their goals, you will need to spend GP/coins to renew their contracts - top managers are expensive (7k or more) but at least their contracts are renewed for 25 games.
Objectives vary depending on the coach you are using and how successful you’ve been in the previous run. At the end of each game you will get a status update on your objectives.
To renew their contracts for free, you need to accomplish a certain amount of points in one of the following competitions (period of 25 games):
In my experience, SIMs are usually the easier ones to pull off, although you can’t really control the outcome of the games. VS COM games are probably the safest bet provided you’re a decent player, but you will have to play a lot of those to secure a free contract renewal.