Just q quick question, how many back up of photo's do you guy's normally make? I have 2 (main pc and nas) and am now thinking of using cloud storage as another option .
It is up to you to decide how many you like. Everyone is different and they do their work in a different way. But no matter what everyone do, it seems there is always a minimum of two. The original and the backed up.
It can't hurt you if you decided to have a third set, maybe even a fourth if you want to. But more than four would be kinda pointless.
If you are thinking of cloud storage, then go ahead, just remember that: Once your files are backed up to the cloud, you do not have any control over what happens there. For example, if the company that runs the cloud storage went bankrupt and closed down, or their data centre had a fire, and they lost all your backed up files. So you would be thankful to have a backed up set on your NAS.
Equally, if some crooks breaks into your house and took your computer, and took your NAS, then your insurance pays you a new computer, you can't get your originals reinstalled from an NAS if it was stolen too, so thankfully you can then download from the cloud.
I have original on PC, main back up on NAS, secondary back up on portable HDD which I then take away from home, so for me that's three. I rather prefer not to use cloud.