I would recommend keeping one at a location other than your home, such as at work, a relatives house, or at a friends house.
That way a fire or theft doesn’t negate your effort. I keep a backup drive at work and bring it home about once a month, backup everything, and take it back to work the next day.
I also back up the real important stuff on a flash drive. Also, I have a separate backup for the applications I’ve purchased along the way (along with a spreadsheet of their registration numbers). I have a number of contingency plans.