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]
(..) That's fucked up. That ain't my fault. It would appear that waitresses are one of the many groups... the government fucks in the ass on a regular basis. Show me a paper that says the government shouldn't do that, I'll sign it. I'll vote for it. But what I won't do is play ball. (..)1992 Reservoir Dogs
(..) but "Like A Virgin" was a metaphor for big dicks. Let me tell you what "Like A Virgin" is about. It's all about this cooze who's a regular fuck machine. I'm talkin' morning, day, night, afternoon... dick, dick, dick, dick, dick, dick, dick, dick, dick! - How many "dicks" is that? (..)1992 Reservoir Dogs