301 - Duration of Transferred PR

When backlink/PR is transferred from an old page location to a new one, over how much time does this continue? How can you tell?

Makes me want to keep the 301’s there for quite some time, given some of the old links. When I drop the 301, the relation ends.

If you Google redirection checker you can find a number of 301 checking services. For me, I can’t think of a good reason to remove an old 301 unless you are bringing back an old url.