In our office, we built contingency plans into our setup. We set up a plan for simple equipment failure and also disasters such as office fire or theft. You can spend a lot of money so you need to assess your risk vs. ability to pay and need to restore quickly.
Simple equipment failure was addressed through redundancy. Having a spare client so that you can simply move from one computer to another is a big part of this plan. Second part is setting up your server so Hard drive and key components can fail without affecting your office. Hard drives fail the most so start there. We adopted RAID 5 setup for our drives. There are many posts on how to configure this and what RAID level. When buying a server, think redundant power supply & network card.
Power outage risk should also be minimized with purchase of Uninterruptible power supply (UPS) like those we bought from Cyberpower
Cyberpower 900W UPS UPS should be on your server and your network gear so they can be properly shut down in an outage.
For major disaster or theft, a strict Backup schedule with regular confirmation of backup confirmation is needed. Some people use Mozypro, AC's backup service or their own manual USB drive schedule. We use Mozypro. All ways work but that one that works best for you will be the one you do consistently.
If all power was off in an office, you should also have printed, blank encounter pages ready to be used. These handwritten notes would then be entered into AC after power was back on. Think Katrina.
I suppose you could print out notes after you do them but I believe that is overkill if you have taken basic precautions securing and backing up your data and implementing redundancy.
Few people have ever lost notes. Although rare, if it happens and it can't be fixed, I would recommend that an office print all notes until the situation is addressed. I certainly wouldn't start doing this though until a note was lost.