Do you mind sharing what backup software you use with your clients?
That depends on the client. My current favorite for home users who want a free option and the least intimidating UI is EaseUS To Do Backup Free.
If something more sophisticated is wanted or needed, or my client is blind and accessibility for taking the backup is an issue, Macrium Reflect Free is my go to.
Backing up, much like safe behavior in interacting with cyberspace, is something every individual has to learn, either by desire or from hard experience with a disaster. Although these things are not therapy, they are parallel to therapy (regardless of type) in that if the person does not want to engage, there is nothing you can really do to improve their situation.
Automating backups to a fixed drive (whether internal or external) eliminates the need for someone to develop a habit and ritual, but it also exposes them to ransomware attacks if the backup is local. For most home users, and even very small business users, that's where the backup is. In areas like mine, where fiber optic internet is just now entering the market, doing backups to the cloud remains very impractical, even though that's ideally where I'd prefer they be. I don't even back up to the cloud, but use two alternating backup drives that are stored in a fireproof box when they are not in use. If I wanted to be really, really careful, one of those would spend its "off month" stored away from my house entirely, but if I were to have a fire, the very last concern I'd have is for my computer and its data. That would not be true for many individuals or businesses.
I want, and prefer, active engagement from the end user. If it's "too much to expect" that they set a reminder once per month (which is usually way more than enough for the demographic I serve) to plug in a drive, fire up EaseUS, and click the backup button, then they really do not care about having a backup, even after having been educated about why it's so important to have one. I've had a couple of clients who have had to learn the hard way, from a catastrophic drive failure with no backup, how much they actually did care about something that their behavior had suggested they didn't give a flying rat's patootie about. Choices about what actions you are, and are not, willing to take have consequences. And they should.
I am not responsible for making other people responsible computer owners. My obligation ends at educating them about what they need to do and, if they agree, getting the mechanism in place for them to do it themselves on the cycle that works for them.