user/instance naming best practices?

[Chris Hecker]

I want to create a bunch of test accounts, and was going to use
instances for these, and I'm wondering if there are best practices here.
 For example, I could do:

checker/test1
checker/test2

and that sort of thing.  Or, I could do:

checker1/test
checker2/test

or even something crazy like:

checker/1/test
checker/2/test

Is there any advantage to any of these?  I've been doing it randomly so
far, so there are even some checkertest1 accounts in there, but I'd like
to have some system I use for this so I can just bulk delete them with a
script, filter them from queries, etc.

Thanks,
Chris