A challenge that a lot of people come across is keeping their files organized when working with multiple devices. For example, I access certain website files from a desktop, laptop, and when necessary from my smartphone (running Android). A program called Dropbox allows me to store certain files that I can access from all three devices without save copies all over the place. When the file is uploaded in one location, it syncs with all locations.
Dropbox provides online backup and sync for free up to 2 Gb. There are packages for 50Gb for $9.99/mo and 100Gb for $19.99/mo. I use the free version because it is all I need for the documents that I want to keep synced between all applications. It installs easily on a Windows machine and there is an app for Android phones.
There is of course alternatives to this problem such as Google Docs or DocVerse (which was bought last year by who else than Google). These provide online storage of documents that also solve this issue, but are typically for files like Word, Excel, Powerpoint, etc. Dropbox allows any file type to be synced so you can run Illustrator and Photoshop files that you may be working on.
Dropbox is also great for multiple users. You can have shared folder access to collaborate on documents that you are working on with your team.