The best low-maintenance repellent I've found is badger. I like keeping a raw badger pelt in the garage and workshop (bobcats are good, but badger's better)... and wiring a paw to the air cleaner in each vehicle to keep them from eating the wiring. I replace them once a year.
no offense guys, but poisons seem to attract more of them, even if it does eventually kill them.... and coyotes eat the cats the first week here.