Say a store discontinued 300 products last quarter. The old URLs still pull a few organic clicks and some backlinks, so what do you do with them? The usual advice is to 301 everything to the closest category page, and I think that's lazy in a lot of cases. Google has said for years that redirects to pages that don't really match the old content tend to get treated like soft 404s, which means the link value ends up on a page nobody was looking for.
For products with real backlinks or search demand, I'd redirect to the closest equivalent product, even if it's a newer model. For the rest, a clean 404 or 410 is more honest and tells Search Console exactly what's gone. I'm curious how others decide, especially when the replacement is only a loose match.