Every bullet caster should have a micrometer.
There is nothing wrong with an old fashioned vernier micrometer, and they can be found for around $10. You just have to be careful to read the mic correctly, something that becomes more challenging as you get older and your vision is not what it used to be.
Electronic micrometers are much easier to read.
Recently Harbor Freight listed an electronic micrometer for $30. I couldn't resist the low price.
After carefully cleaning the faces and zeroing the new mic, it seems to read the same as my name brand electronic mic. The "feel" is fine, no rough spots. It only displays 0.00005" resolution, but that's fine for reloading purposes.
So far there is nothing to complain about.
Here it is measuring a 700 grain bullet for the 500 S&W.
UPDATE: the HF mic is still my "knock-around" daily driver at my workbench. I've dropped it on the concrete floor several times, and somehow melted some of the plastic pieces. The on/off and zero switches have always been temperamental, meaning they only work when they fill like it, which is not very often, so I just leave it on all the time.
Unfortunately, HF no longer seems to carry this model.