Hi,
Sorry to hear about you loss of projects. The advice given so far is really good especially the RAID drive. I have a couple of additional suggestions.
1) I use Time Machine to backup after any session. If I have really been working a project I may back up a few times a day.
2) I use Folder based projects over packages. Makes the backup less storage intensive and faster.
3) Evaluate your regional risks (theft, fire, hurricanes, earthquakes). If your files are valuable consider offsite storage of an archive that is updated every 3-6 months. A copy of critical files stored in a safe deposit box or with a trusted friend will do.
4) Cloud based storage is good for current projects but can be costly for a large archive. One warning is to NOT use a cloud sync folder (e.g. Dropbox or iCloud ) for an active project. The syncing can cause issues when working on the project. Instead copy the project to the cloud storage at the end of a session and update at milestones.
This all may sound like a lot of work but I have all my files dating back 25 years and I have never lost a project.
I hope this helps.