Something so critical as an epi-pen or asthma inhaler, etc. I would keep current.

My veterinarian advised keeping my dog's various leftover ointments, etc that she's gotten for ear/eye/skin stuff. She said they'll be gradually less effective after the "sell by" date but they'll still be useful.

Foods can be fine a long while after the "sell by/best by" date -- which does not translate to: "lethal or unpalatable the day after." Sell by refers to optimal.

It's been awhile but I researched the subject once upon a time and tomato-based canned items go bad sooner because they are acidic. I did that research because I was in the process of making chili and discovered some canned ingredients were months past the sell by. No problemo.

I'll eat eggs (cooked) two or even three weeks after the sell by date (did that last week, in fact). A food scientist friend said that's fine. So far, no problems.