My next door -- townhouse -- neighbor and I had our roofs replaced by
the same guy at the same time, about 6 years ago.

She called a guy to clean her gutters and he said he found that the
black rubber "grommets" (my word) around the plumbing vents on her
house and mine were deteriorating. These are the things that have
a metal cone, with an angled flange at the bottom. The whole thing is
pushed down the pipe that vents the sinks and toilets, etc. and then
shingles are laid over the flange.

Do they make these things so cheaply that they could deteriorate
seriously in only 6 years?

Thanks