What exact temperature allows me to store frozen products really long? For as long as I remember, I was always told (and I was always so sure), that minus 18 degrees Celsius is an optimal temperature for storing frozen products  for really, really long. Months usually and in case of certain types of meat and fish, even up to one year.

Some other sources, that I recall, but can't cite right now, said that in minus 18 degrees Celsius most (if not all) products can be kept until at least "best before" date.

Some time ago I went to a one of Polish shops around me and I was shocked to find this infobox:



It basically says, that in minus 18 degrees Celsius I can store all products up to one month (so not "many months" and not "really long"), with exception of ice cream (which even at this temperature can't be stored for longer than a week+).

And minus 24 degrees Celsius* I can store most frozen products "many weeks". Which leads me to a conclusion that under no home-applicable* circumstances I'm not allowed to store frozen food for "many months" or "really long".

What am I missing? Is above presented table correct?

* not mentioning, that none of fridges / freezers, that I use is able to run at minus 24 degrees Celsius temperature and to be honest -- I have never heard about any home-targeted device, that is able to achieve this temperature.
-24°C will usually be chest freezers, not uprights.

-18°C seems to be generally considered to be cold enough that even new-old-stock mammoth would still be safe, albeit a little dry. The only caveat is auto-defrosting systems in some freezers, they raise the temperature periodically (check the documentation for your model of freezer).