Exactly. I've only got two full grows under my belt, but the rate of improvement makes it so much fun I think. I doubt I'll ever feel that there is no more room for improvement either.
I'm just starting my 3rd grow now, link in my signature. Each grow I've upgraded the grow room drastically. This one now only is solid, only thing I could upgrade in the immediate future are my lights, but I'm reading over 1000 ppfd with them from the photone app when turned to max, so to me it's not a pressing issue.
Maybe I'll hold out until someone wants to sponsor me lol