I'm a bit obsessive, but I have a book in which I write the date that everything I freeze needs using, as I put it in the freezer. I also go through the book at the beginning of each month and hilitthings that need using that month.
I'm not sure about what you have in your freezer, tend to go with Cloverjo, if it looks, smells or tastes wrong when defrosted, throw it away. Five years does seem excessive. You could look on ready meals and see when the useby date is, that would give you an indication of when the item went in the freezer.