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]
(..) He can always get to a doctor when we get back home. Right. - Right. - - Just like a regular parrot. - Yeah. Shape up. - What are you, some kind of parrot? - Right. Come on. Knock it off. Kane's gonna have to go into quarantine. (..)1979 Alien