The most important aspect of a backup is that you are not only able to restore but to do this easily.
The following reflects backups of files, not databases.
The ideal backup tool would create every day a complete copy of the entire data system (including the applicable access rights) on another data system with minimal effort for the administrator and maximal comfort for the user. The computer and hard disk systems to make this possible should be in a distant, secure building, of course. With the help of a file system browser the user could search and access the data and copy data directly back. The backup would be usable directly and restoring possible without problems or special learnings. Dealing with backups would become something normal - since the route over the administration would in general be unnecessary.
The process described here has a ``small'' disadvantage: it needs a lot of hard drive space and it is quite slow because each time the total amount of data needs to be copied.