A good backup strategy has at least one copy of your important data stored offsite – away from your main workplace. So, does creating your own cloud give you this?
In a word – no.
Creating a private cloud solution using your NAS offers the ability to remotely access your files wherever you are. But it doesn’t reduce the risk of a disaster that might happen in the building where the NAS is kept. If you're looking at using a NAS as part of your back up arrangement, I'd suggest making an agreement with a friend to house an offsite backup for each other.
It could work like this. You both purchase NAS units and agree to host them for each other. That way, you both get the benefit of offsite backup and remote file access.
This is also where the established cloud-based storage services can still be useful.
Dropbox, for example, lets you easily retrieve past versions of your files. If you accidentally delete or overwrite a file, you can restore a previous version of the file. If you use the free version of Dropbox, you can retrieve up to 30 days of file history and there is no limit on what can be retrieved if you have a paid Dropbox account.
One of the benefits that a public cloud service like Dropbox offers is that your files are saved offsite. Although there are some risks and considerations that you need to consider when your data is held offshore, it's something to keep in mind.