The buses run from 4 a.m. to midnight 'at regular intervals'. [=there is the same amount of time between buses]
It's nothing special, just a 'regular' [='basic'] stereo. = It's just a 'regular old' stereo.
He is one of the store's 'regular customers'. [=customers who shop at the store frequently]
(..) This cabinet minister, does he always travel on the wrong side of the border? Apparently, they strayed off course. We're fairly certain they're in guerrilla hands. So why don't you use the regular army? What do you need us for? Cos some damn fool accused you of being the best. Dillon. (..)1987 Predator