That’s pretty much impossible with this sort of machine. How to determine if an endmill is done: You need a loupe (cheap, get on amazon) and just look at the tip edges in good light. If you can see the edge, it’s dull. Depending on what you’re doing, it may be fine for a while, but it’s on it’s way out. If it’s chipped, it’s done, just pitch it. The first few times you do this, you’ll probably need to look at a new mill of the same time and alternate between the two. If your finish degrades, you can usually tell (it becomes fairly obvious once you get the hang of it).
Coated (and there are a lot of different coatings) last longer in general, and the type of material you are cutting makes a huge difference (ie. soft wood vs metal), but even more so, how much runout on the mill, and your speeds and feeds make an enormous difference. In my limited experience (I’ve been using a Nomad for about a year), I usually chip the end of a square mill before it actually goes dull, or just plain break one. I suspect I would have more wear issues on a shapeoko where you can use 1/4" mills instead of the 1/8" mills on the nomad. Too fast, too slow (!), both can be a problem for good tool life.
Suggestion: Buy a bunch of cheap mills (if it costs less than $20-$25, it’s cheap) to learn what you are doing, and don’t worry too much about consuming them rapidly…because you will… When you get more comfortable, they start to last a lot longer. It became more worth it to me to use better mills after that.