I like to pull EVERYTHING out every month and give them a bit of oil. I had a group of buddies over this past weekend. Of course, everyone was carrying. So I pulled every pistol out of the safe, everyone unloaded, and we compared 15 or so handguns side by side! That was alot of fun.
Like some of the others, I handle my carry guns every day. Check the one I am going to carry when I put it on in the morning and again when taking it off at bedtime when it goes into the nite stand. Others get a check out before going to the range. I manage to handle almost all of them at least once at least every couple of months, if nothing more than to get it out, cycle the action a few times, practice with getting a sight picture a few times and wiping it off prior to putting it away again. The trap gusn and the bowling pin guns get more action than the more collectables and the carry pieces get the most attention due to their intended use.
Depends, guns that are just riding in the closet/safe get a light oil and maintenance every month or two. My carry firearm gets action checked and reloaded once a day, and cleaned every sunday. (My holster has an open bottom and the inside of the barrel attracts every piece of lint within a quarter mile)
I check my daily carry every day before I carry it outside on me. I usually brush whatever little white t-shirt lint gets in under the sights from wearing CC. Then I also check my bedside as well before bed.