A question for owners of grinders where coarseness is regulated by a small wheel and not by notches around the collar (such as Eureka Mignon).

Is the whole espresso range within one full turn?

If it's not, how do you see where you are? For example, how do you know if it's now standing on half, 1.5 or 2.5 turns?

With the grinder running, keep turning it finer until you hear the burrs chirp. That'll be your zero point. Take note of the number where this occurs aligning with a little bump on the top plate of the grinder, then go coarser to optimal setting for espresso. Mine chirp at about halfway between zero and nine. Most beans I use require a setting between 0.5 and 3.5. most likely you'll be grinding for espresso somewhere in the 1st rotation of the knob.

Ursego wrote:<snip>A question for owners of grinders where coarseness is regulated by a small wheel and not by notches around the collar (such as Eureka Mignon). If it's not, how do you see where you are? For example, how do you know if it's now standing on half, 1.5 or 2.5 turns? <snip>

First, it depends on the grinder. Some are intended for general purpose and some for espresso only. On the GP grinders, the small knob turns quite a few times from coarse to fine. Espresso-only grinders, on the other hand, such as my ZF64w https://df64coffee.com/products/zf64w turn through fewer turns. Also, while some, usually espresso only models, may have numbers on the little knob, on others, the indicator is actually on an exposed part of the burrs carrier.
These examples notwithstanding, the answer to the question is, actually, it does not matter. For example, once dialed in, thereafter when adjusting for bean aging, I turn the little knob only a tiny fraction of one revolution. In the case of the ZF64, from fresh beans to, say, two to three weeks later, I probably turn the little knob no more than about 10-degrees. This means, because of the gear ratio, the burr carrier moves only a correspondingly infinitesimal amount.

Eureka oros have multiple full turns with no indicator which turn you're on. Olympia moca (SD) requires you to take cap off, remove the screw, take knob out, turn the knob, put knob back in, put screw back in, and put cap on. This puts you in a different range.