EsoBackup
Normally I backup my site into a folder every time I make a significant change. I backup all the files as well as the database that controls its content. I hadn't done it for a long time, and I've made lots of changes since my last backup. Thank goodness for stable servers! I've never had any problems where I needed to restore anything significant. The only time I can remember doing anything of that sort was when I switched web hosting services back in March.