I have carried a 642, airweight Centennial almost every day for close to 20 years. Its not alot of fun to shoot, so, it generally only gets shot at qualifications and, the occasional range trip just to blow out the cobwebs.
It is the only gun I own that I believe I may wear out from the outside in. Its starting to look like a river rock from all the wear, nicks and dings.
Every once in a great while, you will find a thread (look at the Smith and Wesson Forum) of an aluminum framed revolver cracking right under the barrel. Some do it when they are new. Some when they are twenty years old. It may be the way they are tourqued into the frame. Who knows. I would occasionally look at that one place, if its intact, drive on.