In the particular case that we want to cut into a metal (e.g 1.5 mm thickness aluminium plate) it will be good to be able to do it in multiple passes (many reasons: save tool life, limited power on the motors etc).
When milling it will be nice to have settings to set the desired depth of cut (what we currently have) but to be able to define tools (that get grouped into a tool list). Each tool should have a custom setting, "tool depth of cut", and if the software sees that the depth of cut is bigger than the "tool depth of cut" it will calculate how many passes will be needed to cut the piece at the desired depth of cut.
As an example let say that we want to cut a 1.5 mm thickness aluminium sheet with an end mill with diameter of 1.5 mm. Since it is recommended not to cut at a depth more than half of the diameter of the tool and since we are dealing with a metal, we choose the "tool depth of cut" of about 0.4 mm. In this case, to be able to cut at 1.5 mm depth we need 4 passes * 0.4 (tool depth of cut) = 1.6 mm (a little over the desired depth of cut of 1.5 mm).
1.6 mm is 0.1 mm over our thickness of the material so a warning should be issued that a sacrificial bed it's required otherwise the tool will hit the router table.
Of course the job can be done as it is right now in multiple steps, each time setting a different depth but since the software potentially can do it, we could focus on something else while the CNC is doing the work.
This could be very useful when doing front panels or maybe when cutting into metal core PCB's (MCPCB's). This feature should be added for the CNC job.