Only reason I have backups is that I shoot 54 to 57 year old Bears. My wife ask me four to five years ago after I bought a good looking '59 Kodiak Special with a few stress lines from one of our really fine Trad Gang members, what was I going to do when that one blew up? So I bought a '60 K Special that was the same length and draw weight.
The '60, which was originally the backup, is now my go to bow.
Later I bought a '61 Kodiak with really beautiful honey colored bubinga from another fine member. Soon after, I bought its backup, a '62 Kodiak of similar draw weight from a member who was downsizing. Hope the '61 doesn't blow as it's a really great shooting bow.