I've got a routine going now, where I've got several working data drives for different things (writing, photography, video, other archives), and it all gets backed up every night incrementally to a larger drive (currently 1TB), except for the flash drive that contains my academic work, and that gets backed up manually in full as frequently as I think I need to (sometimes daily or more often, sometimes every few days).
When my backup drive starts filling up, I replace it with a larger one, the former backup drive becomes a data drive, and one of the former data drives gets repurposed as an offsite backup with ZIPped copies of my data drives that I leave at my storage unit. I don't do the offsite backup very frequently, but it means that if something catastrophic happens, I won't lose everything.
For the incremental backups, I use Iomega Backup, which is no longer distributed, but I like it, because it stores files in uncompressed format that can be accessed normally in ordinary Windows directories without going through any kind of restore procedure and without using Iomega Backup itself. It can store several generations of updated files if needed and you can set the backup schedule to whatever is convenient (I run it automatically in the middle of the night). The usual reason that I need a backup is because a file has become corrupted, or maybe I want to recover some part of a file I deleted, and this seems to cover my needs.
I've had my share of hard disk crashes and such, but I don't think I've lost more than an hour's work since I started using computers for word processing in 1984 or so. Well, I guess there are a few files I wrote using Wordstar on the Xerox 3030 that are on 8" floppies, and it wouldn't be so easy to recover them today, but I haven't had any interest in doing so. I may even have printouts of some of those files, so if I had to, I'd probably check there first and scan them, if I needed them in digital format.