But which troubleshooting aspect(s) of the test account do you envision as being compromised or lost when it is Admin and the account with the issue(s) is Standard?
Well, suppose the problem is a permissions issue: the user is trying to do something for which a standard account doesn't have access. Trying to do the same thing in a test administrator account will yield no problem. Hence, the user—following the black and white reasoning so often employed here—will conclude that there's something wrong with his or her regular (standard) account, and trash a bunch of plists or cache files—as per our frequent urging—and, ultimately (since those approaches won't work), create a new user or reinstall the OS.
Logging into a test standard account, OTOH, would reveal that the problem is not unique to the regular account.
