Old is rarely a good quality in modules with the exception of those which are feature-complete. My general yardstick is 10 years - anything with a release newer than that is probably fine. Older modules may still be fine but I would be looking at a combination of test passes on recent perls, test coverage and open issues to determine how useful or indeed usable it is likely to be.

Recent test passes are particularly useful when considering client modules for hosted services such as the PayPal API. However, be aware that some test suites will mock the API interactions and these can blindly continue to pass years after the real API has changed. Caveat emptor.