Since this site is one where many questions will likely have at least three tags (make, model, part) to begin with, I think it is important to narrow down early which overly-common tags should not be used. This will help avoid hitting the five-tag cap too often, and also make the site look cleaner.
As a starter, I would suggest that maintenance and repair tags are redundant of the expressed nature of this site, and should not be used. There are not currently any repair tags out there, but there's a total of six maintenance tags including one which is mis-spelled as maintainance.