My vet is now requesting fecals for wellness exams - @ 28 bucks a pop! This is separate from the exam fee. I was scolded for not bringing a sample & told to bring it asap. I asked if they were just checking for parasites & was told yes. I played stupid and asked how my indoor cat would get parasites & was told that stink bugs can bring eggs in on their legs & that I can bring eggs in on my shoes! Then the vet complimented me on the cat's great weight & super coat!
My vet always wants to do fecals, also, and for the reasons mentioned. Bugs get inside. I know that my cats are wonderful spider stalkers. You bring stuff inside on your clothes and your shoes. And, it's not outside of the range of possibility that they could catch a mouse that managed to find its way inside. And, who know what that mouse ate.
Insect pests can piggy back their way home with you. Depending on the age of the house/apartment you live in, there could always be mice or other critters running around, providing a little entertainment and a little extra for kitteh.
I have two indoor cats who never go outside, no other pets in my building (that I know of), but both have had fleas before -- fleas that must have hitched a ride from me after playing with the barn cat.
Once a year isn't too big of a stretch for doing a fecal on an indoor cat -- they gotta go in for shots anyway, so might as well try to time it at the height of parasite season so the fecals can be done.