I have about 120.000 photos on my hard drive. I have a back up system (Apple Time Machine) running all the time so I feel pretty secure.
In addition every time I upload photos from my phone , camera etc they are immediately uploaded in the “Cloud”. I have 90 GigaBytes available on Dropbox.
For quite a while I had on my to do list: Sort photos out. I have started last evening and will carry on and off over the next days (weeks?).
A lot needs to be deleted as well. It is major work.