>>2528822oh here's one everyone fucking forgets:
Light.
if things get really bad you will have no electricity or gas. prep light sources. might be worth figuring out if you can buy candles in bulk and if that's cheaper than stocking up lamp oil and storm lanterns.
for the short term: batteries and LED torches/headlamps, but those batteries run out fast and often do not store for long periods. they will literally run out, in storage, doing nothing.