Ummm, those quoins don't actually re-spawn. That doesn't mean you won't get another one on Cebarkul, but probability says it won't be for a while, like several Earth days.

When they do respawn, they are usually in the same place in a street.

Yeah, if we look at my previous photo, it is in fact the same place. We can also see the amount of time that passed!

www.glitch.com/snaps/PUVVI4...

May 18 to May 21 - Just three days! I had really been under the impression that they take longer than that. And, I bet, they usually do. I bet the amount of time is random.