yeah you should just leave things gassed up once its set for the day, its not just timmy's though really, any marker than uses springs in regs will be more consistant if you leave it gassed.
As for grease, to clean/re-grease the Torp and LPR takes 10mins tops to do both. I do it before every major "event" but don't if it's training etc, and I could get away with less. The poppet I do about every month or 2 playing every weekend.
Timmys are very like cockers in that if they work don't mess with them, I don't grease the regs until I need to (like they are creeping or inconsistant say) or take anything apart unless there is a problem.
With timmy's, doing 'preventative' maintentance causes more problems than it prevents/fixes, just turn it on and enjoy until you have to fix something.