Do dry grain products such as uncooked oats, pasta, and rice ever expire?

I’ve read somewhere that uncooked grains never really expire– they just become molded from water contamination or infested with bugs if not properly stored. Also, It is claimed that the Egyptian pyramids have proven that grains can be successfully preserved for thousands of years. So should you really worry if, say, your oats pass the best by or “expiration” date?