But you'll have small distances and large distances and pieces from external sources who use measurements on a scale that makes sense to them. You can make your external sources do conversions themselves, but that's just moving the problem around. There will usually end up being a point, or probably several points, where you have to relate a small distance to a large distance, and wherever that happens, a human sanity check is a help.

> I estimate my bike ride progress in landmarks and time. Not feet per second. Did I get to the boat ramp in 20minutes? Better speed up and get to the park by 30.

Precisely - you have no sense of the relation between your speed and how far you can go, because you're using a terrible measurement system, and you don't even notice the how that's robbing you of the ability to develop useful intuitions.

But one of the systems does have an advantage because it stays in base 10, whereas the other doesn't.

>> Your document lists 12 mass units alone. I rest my case, what could possibly be more logical, convenient, and need less conversion. >I don’t convert, I just pick the unit that fits the problem

But you can't if you just use the `intuitive unit', and that's the whole problem. How would you measure the amount of liquid fuel in, say, the small tank for an attitude control thruster of some probe? How does that add to the overall mass of the whole probe? Or to the force you then need to accelerate it by a certain amount? And now compared to the whole launcher?

In which units do you measure everything going on in a small wind tunnel model, and how do you compare that with the real thing?

Under which conditions do you go from fluid ounces to ounces to cups to pints to quarts to gallons (also note that, again, you not only switch units but bases)?

>Yeah I use the metric system all the time. Just like NASA.

Good for you, it solves all the problems.