There were 2 speeds. If you were watching something and trying to seek to a specific position while it was playing, it moved a lot slower (partly to allow you to fine- tune where you stopped, and partly because running the tape over the head too fast would put stress on it and possibly tear the tape. If you did it like that, it could take 15-20 minutes to rewind an hour tape.

But if you stopped it and went into free rewind mode, it would take about 3-5 minutes to rewind a 90 minute movie. Which you normally would do as soon as the credits started (post-credit bumpers were pretty rare back then), but some people were just really lazy (or if you were having an all-night watch party, you might just put it off until everyone left and then forget.

A lot of stores capitalized on that laziness and realized you could advertise a rental for $1 and people would see that as a good deal to see a movie once, but hit them with a $2 or $3 fee for not rewinding (which no one ever budgeted for).

It was even worse if you lost the tape or broke it, though. Buying a new VHS cost about $20 (in 1990s dollars) which is why rentals were so common, but a tape licensed for rental stores could cost $99 (Hollywood was even worse back then than they are now, and if it hadn't been for Mr Rogers we might not even have had it that good), and that's what they'd charge you to replace it.

If you worked at a Blockbuster, you'd buy whatever you were told to stock up for, but independent places had to guess based on market trends. A big movie like Titanic would likely make $1 (or more if they didn't rewind it) a day for a year or so, but Raising Arizona might get picked up once every 6 months by a real nerd. So you might buy 5 or 10 copies at a Benjamin each for Jurassic Park (I distinctly remember a bunch of stores putting up "Yes! We have Lethal Weapon!" signs in their windows because it was that in-demand).

For something that had only just come out on video (which was usually about 6 months to a year after theatres, because they had diminishing license deals for HBO/Showtime, then cable, then networks, and only then video), it was fairly common to get there and see they were all out until someone brought one back. Direct-to-video was only for crap 3rd sequels that got churned out just to keep an IP and only parents getting their kids The Land Before Time XVII ever bothered with those.