Bought a gargantuan (18 TB!) desktop HDD to be a Time Machine backup for both my internal and overflow external SSD. I’m all in.
I came to this after buying an external drive to make a "bootable" backup of my MBP internal drive using “SuperDuper!” and realizing that doing that is SLOOOOW and possibly pointless. I then realized you can use a single Time Machine on multiple drives. 🤯
Time Machine. What a sleeper hit! Nobody talks about it, but it just keeps on kicking ass after all these years.