I have cron set up to do nightly semi-incrementals on all three of my spinning home machines to an encrypted external hard drive. Once every couple of weeks, I exchange the backup drive at home with one at work. This way I always have reasonably current off-site backups as well as very current on-site backups. My main machine is also RAID-mirrored.
All of this means about $500 extra spinning storage in play. For me, that's a small price for the huge peace of mind of knowing that I really can't lose any work in any plausible way.
About 5 years ago, a friend of mine had thieves strip his house down to the carpets. Everything, including all backup media, gone. He had no employment at the time, so he lost 20 years' worth of digital history, including all his digital photos and all the programming he'd ever done. I decided that if that wasn't enough motivation for me to protect myself properly I was an idiot. I just wish my friend hadn't had to pay such a high price for my lesson.