Robinkae wrote:

My in-laws installed carpet in their home 30 years ago. It was high
quality and vacuumed regularly; it still looks good. However, they
have never had the carpet professionally cleaned in any way (either
steamed or shampooed). We may inherit this home one day. By then the
carpet will be 40 or more years old. Are their any health or
cleanliness problems we should be concerned about?

A forty year accumulation of dirt particles buried in the carpet and
pad. It's up to you whether that's a concern for you or not.

The carpet backing is probably crumbling already, and might be
showing visible decay in just a few more years. My brother and I
pulled 30-year old carpeting out of his house. While pulling it up
it tore almost as easily as paper. Turned out the backing was
brittle and crumbling.

HellT