Can you still get nicotine there? A lot of mixers get 10% nicotine and store it. We can still buy it in the US but it could disappear any time so many of us have picked up a lifetime supply. It will last forever in the freezer. I did hear a while back that folks in Aus still get it from China. They will ship it with a label that calls the contents something other than nicotine so you have to just cross your fingers and hope it gets through customs. Not sure if you would be in trouble if it gets caught, other than losing your shipment.
They say VG and PG will last a long time just in a cool room. Flavorings for mixing will always be available since it is used in food prep and other places, vaping is a tiny % of the market. The storage rules are a bit unclear. Some flavorings will last forever on a shelf, others will go off after a while. My favorite vanilla went bad after a year. Heard different opinions about putting it in the fridge. Or were you talking about mixed juice? That can go off, sometimes quite fast. No idea whether the fridge will help, freezer is definitely a no-no.
If you are thinking about the long term nicotine is the biggie. That's the only one which could become hard or impossible to get hold of.
Vaping gear could be off the legal market as well, but you can get that from China. They ship it with a label that says filters or something like that. Customs can't open a million small packages looking for the one that might be a vape tank.