One of the most important feature that you should look for in an online storage service is their data recovery policy. How are they efficient in backing up files and data retrieval?
Some online storage providers allow their users to go to previous versions of the files and restore the data that they need based on the date of the last save. You can also direct where to save the data you wish to restore and it also prompts if you want to rename the file or not.
If you want to keep track of all your files, there are also some providers who keep deleted files on their server. No matter how long they stay there, they are never deleted unless you told them to. Data are retained as long as you want to keep your subscription active.
You should also know about the recovery policy your providers offer. Do they delete your files once you fail to pay them the monthly cost of their service? What happens if you decide to close your account? Most companies give delinquent account owners a grace period of one month to download their files once they decide not to use their online storage any longer.