Major improvements in its plots make this new utility even better for tracking changes in used space, and so forecasting how long backup storage will take to fill.
DeltaFree
If you leave your Mac running overnight, but not sleeping, what does it do? Does it perform maintenance tasks that it would otherwise have to do during the day?
Nine days of measurements of used space on a Time Machine backup storage drive. What does DeltaFree predict for its lifetime? How does used space change in containers in the internal SSD?
To work out how long you’ll be able to use your present backup storage, you need to know how much space is free now, and the rate at which free space is being used by further backups. This app can forecast that, and more.
The Eclectic Light Company 