Agreed, it is SO important to pick feet and I see people who don't do it at all! I'm sure your mare really appreciates being put back with clean hooves, too!
I just started boarding my horse and the ground isn't quite as nice and dry as my old stalls. Ive started to get fairly anal about hooves. I find myself picking them before rides, after rides, during bath time, before and after turning out, and whenever I clean stalls.
I am also a new horse owner, and every time I get him out of the pasture- even if just for grooming & not riding- I pick his feet. I also rub him all over before brushing to look for any cuts, scrapes, lumps, etc. I love my new boy! :)