It is July 7, and I have already run out of my monthly Comcast data allocation. I get friendly e-mails every few hours telling me this. It will now cost me $10 for every 20 GB I use.
I am not really sure what app did this since I do not stream many videos. I suspect that It was Picasa that saved all of my pictures. Or it may have been Amazon Music that spent 3 days trying to upload about 900 "missing" albums from my 76,000+ track lossless music collection. Or it may have been the Piccure+ app that spent 5 days deconvolving a few thousand photos to remove micro blur. Since Comcast didn't notify me until I had already used 90% of the allotment, it is hard to tell.
But the larger point is that existing ISP contracts do not give serious users enough bandwidth to move large amounts of data to or from cloud storage. None of the reviewers of cloud options (Dropbox, Box, Google Cloud, Microsoft Cloud, Amazon,...) seem to mention this.
Hard disk storage is cheap. You can get a small 3 TB drive for about $100 now, so there is no reason not to back up your own data on an external drive (or two, or three). You can even put one in your safe deposit box in case your house is destroyed. Because my Music collection is so valuable (due to the many man hours I spent to create it), I have five copies of it on 3 computers, each on a different physical disk. And I have managed to wipe out two of these at a time, so perhaps I am not that paranoid.
Besides, for your computers, you want full backups of your boot disk so that you can restore a dead boot disk without spending days reinstalling all of the applications (and finding them and their registration keys). Apple's Time Machine, and Windows Pro let you do these full backups. So does Linux.
It is a shame that Windows 10 is trying hard to marry you to their online storage. I would not trust them with my sensitive data, and they cannot backup my several TB boot disk.
I do use cloud storage for some things. For example, Dropbox holds files that I need to have access to no matter which device I am on (computers, phones, tablets). It has my encrypted password file, my consulting hour time sheet, and my software registration information. I also use it to transfer large files to friends and colleagues.
Rather than wasting $10 a month on Apple Music, Pandora, Rhapsody, etc, (all of which have sub par audio if you have a good system), I have my own Subsonic Music server which I can access from the Internet (next month when I have more data usage from Comcast). It also serves the kind of music I like!