I like to keep tank maintenance to once a week so i never miss it. I do whatever is needed every sunday evening 2hours before lights off.
I usually clean filters etc on a week where i am not doing any trimming so i can perform what is needed within 2hours.
I would say naturally i do plan big trims, but recently i've been trying to concentrate on shape, so ive been doing little trims.
I trim the massive amounts of crypts every month to thin them out and stop them blocking light in some areas. I trim the h.pinnatifida every month too, only trim the big vertical stems and it seems to grow very quickly.