my old football boots

Might be getting back into some 11 aside friendly games.
Amazingly my old football boots mouldies still look ok, god knows how they have survived through house moves etc.
However they are 20 years old.
Should i just go and buy new ones or will they be ok?

This. It's frightening how much 'football fitness' you lose, even if you are otherwise fit and healthy, if you don't play for a number if years let alone 20. It's the fast stop/start twisting/turning etc. that puts so much strain on muscles and tendons that just being fit running/swimming/gyming doesn't prepare you for. I played an hour of 5s after a 7 year break. I was destroyed.

I think the boots are the last thing you need to worry about, good luck!