Ugh, been debating with a client for an hour about basic backups and security practices and want to tear my hair out. How do you guys deal with stubborn clients?

Don't fight it. Explain that you completely agree with them in some way, and that's why you're saying what you are saying, and should be done your way. People don't like being wrong, so make them feel right and convince them that way.

Sadly, @620hun is absolutely right.

Forcing someone for his own good is what you do when your best friend wants to sell his house to invest in the selfmade-jewelry business of his since-last-weekend hooker girlfriend named Kristy.

@Kiwi welcome!

Don't argue, just say No. It will transform the discussion.

With backups its best to talk about disaster recovery senarios and costs and types of failure

smile as politely as you can. the calmer u are in that situation, the more the client will tend to listen because he/she will see that you are confident about what youre saying