Disk space management

[Mugen]

what is the best way to work out disk space management for backups.
as far as i can tell it's a bit hit or miss and the only way i've found to work it out so far is waiting till it fails.

[Mildur]

I am planning my required disk space with this tool:
https://rps.dewin.me/

I always buy storage for at least 1-2 full backups more than the calculator tells me.
I know how many restore Points I need before I buy my Storage. This helps me, that I am never short of storage.

[Mugen]

thanks for that info, much appreicated