As far as I understand, you created the repository via TortoiseSVN and access it locally on filesystem (i.e. via file://
scheme in the URL), you are the only one who is going to access the repository.
In such case it still makes sense to backup the repository to an external storage from time to time. It will assure that you won't lose your versioned data in case of local storage corruption / disaster / whaterverhappens.
As the backup method, I can suggest to use svnadmin hotcopy
or you can copy the repository directory using built-in OS tools (e.g. via Windows Explorer or FAR). If you copy the repository using Windows Explorer, make sure that the repository is not accessed by anyone at this time.
If you use Windows Backup (Volume Shadow Copy backup) on your machine, then you can easily configure it to backup the repository on schedule.