Ruby, If that happens to stuff from your freezer after 12 - 24 months, then either
your freezer is not doing the job properly, and you need to replace it
or
you don't wrap the food adequately and it gets freezer burn.
A good modern deep freeze should keep food 'deeply frozen', and the decay process is virtually stopped (altho the food does need to be fresh/in good condition when it is first frozen).
I would expect something simple like mince to keep quite happily, with little deterioration over 1 to 2 years.
We did ditch some smoked salmon which had been in the freezer for 2 years. It didn't taste nice (tho not dangerous in any way).