I write down the day I opened something that has a short expiration date "after opening". Such as milk, jam, jogurt etc. Because I never remember when I opened them and while 3-4 days might be save a week is often not, even if the product doesn't seem or smell weird at first glance.
I don't do that with frozen products because in my opinion frozen products don't go bad unless they defrost and get frozen again. I won't be keeping them for years anyway. If something stays a year in my freezer it's either something I don't like or don't need or am afraid to eat so it gets thrown away on the next freezer defrosting.