Penis Envy shelf life?

Hey everyone. Fairly new to the shroom world. Wondering whats the shelf life (expiry date) of any average shroom? Also, are there ways to preserve it? Refrigeration?

Every place Ive seen usually sells a minimum of 7g. Im curious if I can have two seperate sessions (3.5g each) in a span of around 10 days with the shrooms not going bad!

Always curious to learn! :)