Hard Disk Crashes
One pro-tip for avoiding crashes: stable tables and steady connections! Having a storage system in place for saving all projects, backing up and working off of is not as simple as buying the first 5TB hard drive that shows up online. Factors like file formats, HDD speed, connection ports, etc has to be taken into account.
Even then, necessary precautions must be taken in case of a crash. Indexing your drive being one them.
Learn more on this subject, here.