I have to say that when I'm in the grocery store I'm in the habit of looking at the expiration dates but that's soon forgotten if it goes in the freezer. Because the holidays were basically back to back my freezer seemed more crowded than I liked so I began to clean it out. Well those forgotten food items now presented themselves with expired use by dates. I'm thinking is this still any good? But because it is past the expiration date I just toss it. How long would you or do you keep items past their expiration date, perishable or non-perishable?
It depends on what foods is past its perished date and how it appears. For any meat foods that have past their perished date will be a big no no for me to eat if it is not frozen - if frozen and with no freezer burns, I will thaw it out and eat it later. As for vegetables, if it still looks and smells good to eat, I will use it still; I will do this with fruits, nuts, and mushrooms. Dairy products that are past their due date I throw out because I had a few bad experiences before. Canned foods I will keep even after expiration, because one can only truly sense if it is rotten after you've opened it. As for chicken eggs, I do the simple egg drop in a cup or bowl of water, for if the eggs rises it is no longer good to eat.
A lot of things can be frozen forever (or at least months)- that is why a lot of meat now says 'cook or freeze by' and then a date. So if you put things into the freezer by Christmas, and when you put them in the freezer it was before their expiration date, you are PROBABLY good to go. Google the specific foods to see how long they keep frozen- I think in most cases you will be very pleasantly surprised how long they can last in a freezer, as long as they were frozen BEFORE the expiration/use-by date.
One thing you should know that most items have a sell by date and a expiration date. Though, most often you will see that they just use the expiration date as a general time to sell their products by. The fact is that something that says it expires tomorrow could still be good well into next month. A lot of our foods have preservatives in them that make them last well beyond what they normally should expire.
I keep the goods after 30 days, but after knowing that they are already expired, I use them right away or as soon as I could within the 30 days. I just don't throw them right after. I have read that after the expiration date, the goods they designate aren't really expired. Just that some of their freshness diminishes, but they're still edible. Don't mistake this though that foods don't really perish. They do, so it's still best to be guided by expiration date. Also it helps to maintain the freshness of the goods after they expiration by stocking them in the freezer, and only heating them when you are going to eat them.