I'll second what Lee said, if you don't need to, don't detail strip it. As many years as I've been doing this, I have yet to disassemble the 870 trigger group. No need to. I've taken the 1100 carrier off to install a larger release and I've taken the bolt apart on the 870. And I'm meticulous about cleaning.
MOST wear and breakage is not a result of firing the guns, it's slipshod and/or unnecessary disassembly and cleaning. Now, I've put a few back together that people I know have taken apart to "clean". When I clean my guns, I field strip, spray them down with Break free, scrub with a toothbrush, then blow the excess Break Free off with compressed air. Wipe what's left down and reassemble.