Hi,

It depends on what you want to backup and how you would like it to work.

There are things like "Windows File History" and "Synology Cloud Station Backup" which work by monitoring specified folders in real time and keeping "versioned" copies of any files that change somewhere, like on a NAS unit.

Then there are things like "Acronis True Image" which take snapshots in time of specified drives, partitions, folders, etc.

While you can run this type of backup on demand typically it will run on a schedule.

Some backup applications will only backup to local devices like a NAS units, others offer backup services to the "cloud" - these usually require an annual fee.

I use both types.

Frederick