Millions,
Yeah. That’s the question. How many minutes can each side of a 7 inch be? Your knowhow is thoroughly appreciated.
A 7" record holds a maximum of about 4 minutes of music per side at 45 RPM.
That’s not true at all. The single version of “Hey Jude,” for one example, is timed at 7:11.
While the jury is still out, what about 10 inches? Running time, I mean.
Ok: I pestered a friend of mine who presses records (and was SUPPOSED to be out of town. Pays to ask I guess). The answer:
8.5 minutes at 33rpm
6.5 minutes at 45rpm
The end brushes off hands
Suitably ashamed by my earlier polluting of the SDMB waters with further ignorance, I just got off the phone with Aardvark Mastering, a company that presses vinyl records (and makes and sells the plates you use to press them yourself). I was told that it’s usually 4-7 minutes, but you can push it further at the expense of volume and high end detail. He says he’s pressed records at up to 9 min per side on a 45 RPM 7", but beyond that is really noticeable.
Your follow-up is commendable and, nicely, fits in with what I’d discovered as well.
Well, I tossed off my first answer after a glance at my own collection of 7" singles. Of the 50 or so, the shortest side I could find was 3:06, and the longest was 4:25. I concluded (reasonably, I thought at the time) that if you could fit more than 4 1/2 minutes of music on a side, at least one of these artists would have.
What I didn’t take into consideration is that basically all of my vinyl is punk rock. 4 1/2 minutes is often at least three songs. 
Pretty much every 7 is a punk 7 these days, isn’t it? Does any other genre really use 'em?
Indie pop and reggae.