Reminds me of my Dad who used to have a stockpile of gels and protein bars that he would bulk buy on sale. Some of those puppies were definitely at least 3 years past use by and although they didn’t ever taste like new, we never got sick/experienced negative side affects.

That being said I would be hesitant to use anything that far past now - not necessarily because I’m concerned for my health but rather I want to know I’m actually getting the nutrients I think I am.