I think it's important to separate performance/playing out from production skills - good producers obviously evolve with time and you may or may not like it, but as Henry said, musicianship stays with you forever... however, as you get older, performance and playing out 3-4 times a week gets draining and boring - the enthusiasm disappears and there's no way to hide it as a performer - it really comes through to the audience and if the boredom becomes contagious.

machina