"
If it is worth doing, it is worth backing up!"
I have witnessed several colleagues go ashen-faced when their non-backed-up hard drives failed. One had to go to our departmental manager and explain that he had just lost the mission-critical report that he had spent a year writing (at a cost of £20,000+)! Let's just say that the meeting did not go well...
I remember another example of a dead HDD. The company sent the drive to a specialist who disassembled the drive in a 'clean room' and rebuilt it. I think they managed to salvage most of the data off that one but it caused several weeks delay to the project and cost thousands of pounds to sort out.
Every now and then I backup my entire SSD to an external USB hard drive. I backup my documents folder daily to USB flash sticks, alternating between two so if one of those fails as well as the drive in my laptop, I still have a one day old backup.
It is advisable to keep offsite backups too in case of fire/theft - you could easily lose the backups as well as the originals if they are stored in the same place. I have left flash drives with a friend elsewhere. I will probably start backing up to OneDrive too.