What is your experience? Do you store seasonal produce when in season or do you rely on the supermarket alone?
I rely on the supermarket for produce. Seasons don't seem to matter there.
There are certain fruit and tomato varieties that appear in the summer at my local farmers market which would never make it to a chain supermarket. These I can (using a boiling water bath) so I can enjoy them in the winter but don't have to dedicate limited freezer space to them.
Freezer is dedicated to sale items - poultry/meat/butter - and homemade basics. Homemade chicken stock and tomato sauce. Doughs, since it is easy to make extra and freeze the excess (bread dough, pizza dough, pastry dough, pasta dough). White sauce and cheese sauce. Rendered fat (chicken and pork fat)