Although maintenance on the slider pins and such is never a bad idea..it usually won't help a sticky piston unless there's a big "chunk" of something jamming it from the exterior which is unlikely. Typically when pistons start to stick it's because of corrosion or something internally which you can't get at without tearing down the caliper and rebuilding it, something most people won't or can't do. Replacement is easier, and usually cost effective. If you know how to bleed brakes at home it's not something that a backyard mechanic can't do, either.
