For a while I just routinely bought backup stock. At this point I'm good well into the next century.
Really didn't notice the great tube shortage at all.
I was already thinking of getting an additional set of spares when the invasion looked eminent. So I bought one extra set. Enough to last me many many years. It was way ahead of the “scare”.
I had a couple of friends who lost tubes when things were at the worst. They couldn’t find the tubes they needed. I got mine cheap and had a decent stock of AX7s. I Just gave them away to the “needy”.
One of the guys is a very good guitar player and is offering his talents in the studio for my next release. Ended up being a great swap!