I buy 5 lb buckets(2 sizes) of NLS!
They can easily last 1-2 years if stored properly.
Remove as much as you will use in 1 month or so and re seal the rest.
Store in cool dark place(my fishroom is in basement so this is easy for me).
Some actually store in freezer to help extend the freshness.
Here's a link from this site and a "response" from NLS in last post!
I searched for 4-5 star foods and just couldn't find any in my area in BULK.
I have also since added kensfish earthworm and blackworm flakes to my fish menu.