This
There are one or two threads on Hexus that do get bumped, once every couple of years, because someone found it on a google search (active forums rank highly on google) and it solved a problem they were having (getting MS Pro Duo cards out of an SD slot was one example). When they register to thank the original posters the thread gets revived and google will rank it more highly, which means it has a better chance to help more people. Plus, there's always the chance that some of those people stick around and become valued members of the community.
So as a general rule we won't close threads just because they're old or "finished" - you never know when a thread will come back in to fashion