Different kinds of posts have different policies, IMHO.

I'm with Richard on BUG's: they should never be closed.  If we have 1000
old bugs, then tough.  They need to be fixed, and that's all there is to
it.

FIX's are trickier.  If a FIX is associated with a BUG, then indeed it
is simple to deal with: it lives until the BUG is closed.  However, a
lot of FIX's just describe the problem they solve in the text of the
message.  Essentially, such a FIX seems in fact to be declaring a BUG,
and so surely it should be left alive just like a regular BUG until it
gets reviewed.

ENH's are different.  An ENH is something that many people may have a
harder time seeing the value of, while no one sees a negative impact. 
An ENH seems like something good to time out.  The closest alternative
that seems to make sense is to have people explicitly post that they
don't know whether the ENH is any good, and to close the report whenever
3-4 "don't know"'s have accumulated.  This sounds like more work than it
is worth, however.  The current policy seems unworkable for ENH's: it is
extremely possible for no one to have an opinion in either direction on
an ENH, in which case it will stay open forever.  6 months seems like an
entirely reasonable time frame to me; it's long enough that it is pretty
obvious no one is going to review it, and short enough that the logs
should not get insanely polluted.


  -Lex