> There are places that have it still, and I’m trying to figure out how many months to get. <
A friend of mine has had problems with dry dog food - it gets moldy after a few months. So consider putting some in a freezer. I believe dog food can last for at least six months there.
https://www.wikihow.com/Store-Dog-Food
#12 Freeze some cats : )
Use a Foodsaver bag....
Vacuum sealing and mylar w/02 absorber sealing helps.
Another option besides the freezer, if you live in the north, is to secure it on an outdoor porch during the winter months.
Once winter hits and the temperature remain below freezing, stuff that it is not critical remains frozen solid can be stored there.