Over
time, a window may deteriorate due to the enviornment it's been in and
whether or not it's been subjected to forces other than gravity such as
being in a door that opens and closes (slams!). In some cases, only the
solder joints need to be resoldered or it needs new putty where the old
putty has fallen out. In severe cases, the entire window has to be
disassembled, and rebuilt with new lead or zinc came.
