To be honest: yes i have 2
But here is how i prevent destaster: i frequently backup the OS drive to the data partition. If my OS drive breaks i will use my backup drive with the backup image or i just order a new drive. no drama and no different to using USB sticks (well just the price maybe).
(I ran into another guy on this forum who had SSD's, in quantity, laying around, doing nothing.)
With that said, when using USB sticks, a boot drive replacement is a matter of simply plugging a clone into the front panel. Very easy.
On the other hand, I have to give credit where credit is due. You're one of very few on the forum who has thought about, and has actively planned for, disaster recovery. Don't stop with the boot drive. Give some thought to backing up your data as well. If you look at my signature, I'm using an R-PI for that purpose so it doesn't have to be expensive.
(As if you're worried about " the cost". )