Availability and price goes up/down every so often. How long the lean times last varies as well.
I have two pieces of advice.
1st is, when you can get different components buy some and experiment so that you have more than one good, accurate, reliable load for your favorite shooting/carrying guns.
2nd is, don't wait till you need something to buy it. If you see a price you're willing to pay, buy it. Put it away. Store it right and it won't go bad before you can use it. I've used 30 year old primers and powder and there was nothing at all wrong with them. I'm sure others have used components older than that.
Right now I've got multiple old powders I know will work in my handguns. Red Dot, Green Dot, Herco (yeah, all shotgun powders, too). I have good accurate loads developed for my .223 with BLC2, IMR4198 and H335. Have good accurate loads for the .30-06 with IMR4895 and TAC.
Working on handgun loads with Win 572. Have some Shooter's World powder and just bought some Vihtavouri powder to try as well. We all know what works well in our guns but we should be testing out other components when we can.
Who knows, you might find something that works better than your old favorites.