Please, please. Back up your computer on a regular basis; a very regular basis. AND, don't just use an external drive.
This story isn't about me; it's about YOU. Last night, while my husband Walt and I were at a 70th birthday party for a friend (we were gone a little over 2 hours), a group of about 3 (according to a neighbor) broke into our house. Long story made very short, but a friend had come to the backyard, saw the broken window, ran to the neighbor's house and he called 911. He also saw the group run out of our yard. So, he knew there were at least 3; he knew what direction they ran, etc. Not too much was taken, but three bedrooms were ransacked (YES, horribly). Walt and I are OK, except this morning we're tired; didn't sleep too well last night. Now we just have lots of cleaning to do, insurance company to notify, locks rekeyed (just in case), etc.
So, where's the story about you? This group dropped some of the bags in the back yard. In them were 3 computers AND my external hard drive: where all of my backup files are stored. I've been meaning to get cloud storage, but just haven't. This week I'll be doing a few things differently, in case you hadn't guessed.
I guess what I'm trying to say is use something that is not near your computer when you are backing up, because something may happen to both the computer and the external device.