I don’t even stock a spare. It’s not life or death since I have electric resistance back up heat that should work. The new cat from amazon can be on my porch in very short time. Plus the cats don’t fail like a light bulb, it’s quick but not that quick. You can run with a pretty worn out cat while you wait. Just run it more like a noncat and it will burn relatively clean.With the exception of people like highbeam and Poindexter, I just don’t see much need to keep a spare, considering they last many years. I can see buying a new one once the original has some age on it and holding onto it until it seems necessary to change it out though.
If I lived in rural Alaska I would probably own a spare.
I did notice a 10-15% price increase since 2017 when I bought my last one.
Just got done blowing mine out with 50 psi compressed air just for good measure!