I always took the dates on drugs like this as a potency issue more than a safety issue. After the date it won't hurt you, but it may not be effective. (Not sure if your friend would confirm that or not, just what I had generally assumed.)

As far as food, I do look at dates. We don't have overstock of much, so this isn't a problem. We do have some canned things around for a while, but cans are usually good at least for a few years and sometimes aren't date marked at all.

If it's something unopened and close to the date, I'd probably use it, at least the once, and all of it if it will be used up quickly. Months out I probably wouldn't touch it. I can't imagine having things years out of date, although I do have some few-years-old spices around, yeah, as seems pretty typical. (Again, mainly the issue is they aren't effective, not that they'll hurt you.) They really ought to put "best if used by" dates on spices, something about a year or two out. (Maybe some do, I dunno, but I haven't noticed.) To a degree it's a guide, but one I generally adhere to. Stuff like meat/dairy/bakery has unusual dating as "sell by", which doesn't help much. Meat is always use or freeze within a couple days of purchase. Dairy would be using within a week or so of opening, which is sometimes earlier than the sell by date. And so on.