Players with skill always retain it. Del Piero, Zidane, Raul,Toni,Etoo,Drogba et al...will always have the moves and plays in their heads, even when having 60 years old and being crippled. As long as their body goes on par with their judgement, we are good to go.
Also we need to remember something very important. Drogba has an athletic frame by nature. UNlike players like Cassano and Pepe who are not born athletes, players like Drogba have it easy to keep the good form. Take that into account.