I haven't ever been backing up my data, with luckily no problems so far, but I figured I'd want to get started at least making a few backups a year to an external HDD.
Googling for this just yields a bunch of software that's either commercial or oriented towards cloud synchronization, and sites generally don't agree on what to recommend.
Basically, looking to just backup data, not software. I can always redownload software / reinstall my OS.
I'd rather keep multiple versions of the data than just one, allowing me to grab a version from a few backups ago.
I'd really like something with as little friction to use as possible. I'd nearly be up for just Ctrl+C, Ctrl+V the folders onto the external HDD, but that ruins the creation and modification times, and probably doesn't account for other such details.