Towers at military fields issue a "check gear down" instruction along
with the landing clearance... I always thought that would be a good
idea for GA also.

It usually takes a while to get a Comanche slowed down enough so extending
the gear is more of a necessity. I usually keep my speed up pretty well
until closing in on the field which practically forces me to reach for the
gear lever to get slowed down enough. But things such as long straight in
approaches, or getting slowed down further out can lull you into a sense
of comfort. There's just no substitute for doing the GUMPS check religiously.