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]
(..) coffee, TV shows... ...surveillance systems, all history books, voting machines. Come on, you can't be this stupid. I'm just a regular, normal, ordinary guy. I'm late to meet my best friends in the whole world. They're probably missing me right now. (..)2014 The Lego Movie
(..) -Charlie. -On your way somewhere else? -Passing through. Looking around. -Funny to see you. -Funny, isn't it? You boys are a regular family business. You boys are a little late. -What did you find? -I found some interesting prospects. Did you hear Standard bought up? -Mostly in the north, so far. (..)2007 There Will Be Blood
(..) 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