From a previous discussion:
So yeah, it’s totally fine. I’ve often found something at the back from years previously and eaten it. The main problem is if you open a packet of something and don’t wrap it up properly when you put it back. You then get lots of ice crystals forming around the food which makes it soggy when you defrost it and (depending on the foodstuff) often makes it unpalatable, but is still completely safe to eat.
Yes, 100%.
This is one of the biggest revelations I’ve ever had, like discovering aliens exist. Mind. Blown.
Similar. Moving into a house a couple of weeks before the second year of uni started and finding a freezer half full of meat that had been left there by the previous student tenants. No idea how long the electricity had been off in the weeks that had passed between then leaving and me arriving, but, same as you - it still haunts me. 
This happened to us too 
This world.
I’ve got a PAYG electric meter. It quite often runs out and everything goes off. Sometimes i’ll be at work and it’ll go off for hours, or it can go off and i’m away. It was off for a week once when i was on holiday. I don’t really buy frozen food, but there was a load in the freezer from years ago that other people must have bought. A mate stayed with me temporarily and i told him to help himself to food and toiletries, etc. He demolished most of the freezer. There was stuff in there that was five years old at least. There was allsorts in there, including fish. There were admiral pies in there that would have thawed and refrozen several times over, and he ate them and he was absolutely fine. Stomach of steel. Madness.