While you can still purchase vinyl dryer ducting at most hardware stores, one of my personal “peeves” is to have it replaced with metal ducting, ideally smooth metal ducting. Dryer lint is highly flammable and vinyl burns, so it doesn’t make a lot of sense- at least to me- to use vinyl dryer ducting. Smooth metal is best because it doesn’t have corrugated folds that can catch lint and cause it to build up, but flexible metal is good if smooth metal isn’t practical. I always recommend replacing vinyl dryer ducting when I see it. This was noted at a recent home inspection in Friday Harbor on San Juan Island.