I stock 200-300 rounds of JHP's for each caliber I shoot.
You don't have to do it all at once. Keep a couple of mags full of your carry ammo and a box on the shelf. Then, as $$$ allows, add a box or two until you have a couple hundred rounds or more. This should give you enough to shoot a mag or two when you like, and get you thru any future shortages.
As for target ammo...I just keep buying!