Consistent and/or customizable number of decimals places for values
v 22.0.1
Most of the Features in Illustrator have inconsistent number of decimal places.
New document size — 3 decimal places, 0.001
Artboard size — 2 decimal places, 0.01
Artboard position x,y (in the same window) — 1 decimal place, 0.1
creating new rectangle — 4 decimal places, 0.0001
Object transformation — 3 decimal places, 0.001
Rectangle angle — 2 decimal places, 0.01
Rounding corners — 3 decimal places, 0.001
Split into grid — 2 decimal places, 0.01
Offset path — 4 decimal places, 0.0001
3d revolve angle — 0 decimal places
3d Extrude & Bevel angles — 2 decimal places, 0.01
3d Extrude & Bevel — extrude depth — 2 bevel height — 0 decimal places
3d Rotation everything — 2 decimal places, 0.01
drop shadow dialogue — 2 decimal places, 0.01
Move dialog — 4 decimal places, 0.0001
Pattern — 4 decimal places, 0.0001
Blend — 2 decimal places, 0.01
Let's look at the example user journey:
In my workflow I am building an illustration of isometric sport games layouts.
As Illustrator has an working area size limitation i am forced to keep the illustration in certain scale. and for smaller objects I have to create bigger versions of 3D elements, then through symbols/CC library scale them down. Otherwise the limitation in number of decimal places of the 3D effects doesn't allow me to keep the proper object shapes.
The number of decimal places in Transform tool is 3 (minimum 0.001)
The extrude Depth field has a soft cap for 2 decimal places and minimum value of 0.01 pt
The Bevel Height for some unclear reason is limited to zero decimal places — 1 pt
Both have to be 3 decimal places a minimum value of at least 0.01 pt

Speaking of precision, can’t but recommend a free script to round color values in a selection, using a set precision. Great for trimming fractional values when needed.
https://github.com/gau/roundingcolorvalues 
Ajay commented
Allow edit artboard in properties menu to accommodate 34 decimal places rather than rounding it off.

Remember team — always make everything you change as an option. Anubhav said recently, presenting some features, that you 'learned not to change defaults', right? And then immediately presented new Simplify, thus killing the old one, LEGACY, team, LEGACY. Two decimal positions, three position, any number a user chooses. Same with Yaxis — just bring it back already as an option! Valid one!
(Edited by admin) 
Tommi Koski commented
Can we please have option to use only two decimals on units.
We use millimeters and four decimals is waaaaaay too much. Two is just enough. Example what we have now 1200,0000 mm, 1200,00 is what we want.Tommi Koski Tarrateksti **

Javi commented
It would be nice to be able to configure the number of decimals we want to work with in Adobe Illustrator. There is a total inconsistency in the number of decimals that Illustrator currently works with, since the artboards have 2 decimals, the object transformation before version 24.1 had 3 decimals, after 24.1 4 decimals, etc. It is very uncomfortable to work with such a variety of decimals, it is also not accurate.
It would improve the workflow and accuracy by being able to manually configure the decimals we want to work with.
Hope that helps. ;)

John Miller commented
I don't understand why we don't have this decimal problem in Indesign. Why does Illustrator has to round it up?

John Paulhus commented
I'd even suggest 4 decimal places to get perfect 16ths (.0625)

John Paulhus commented
I really want 4 decimal places to be the standard across all Adobe CC programs. How else could we get a perfect 16th (.0625)?

Christopher T. Calhoun commented
The issue in particular I have is that artboards only have 2 decimal places in inches. Float that ****** out to 3.

Anonymous commented
The ability to design in ONLY whole number, giving us a checkbox to disallow decimal values for size & transform.
I spend much time correcting the decimal values that pop up randomly while designing and it is rather frustrating. It would be great to have a way to allow ONLY whole number values in location & size. See attached. this happens with .5 values as well as things like .812 which make it really tough trying to align!

Valerii Mamedov commented
Thanks for the answer, I hope you will bring it to a logical solution flexible and consistent.

Thanks for compiling this and sharing details of your workflow. It definitely helps us understand the issue better.
As we gather, there are two parts to the issue  one, there are different decimal limits in different places, and two, this difference is leading to precision related problems when you use scale factor in your measurements. For the first part  it would have been easy to solve, if we had just one unit to deal with. Illustrator handles 8 different units simultaneously and each have their own logical scales. Units like Pica or Q/Ha, or even Inches, require a different treatment than mm/cm. An input in one unit, has to be converted with its best possible accuracy to the working unit. This is not to say that anomalies do not exist. And as you've pointed out in the examples, there are different decimal inputs limits in different places.
What we are thinking is to build a consistent decimal limit, for each unit in all places. But it would still be possible to see different decimal limits for different units. Maybe, we even expose decimal control for different units, in the UI. Maybe.
For using scale factor, building a consistent decimal limit for each unit, should solve the problem to an extent, but ideally there needs be a different solution for that problem and we're exploring different possible options around that.

Jim Hargreaves commented
When creating a new document, Illustrator CC rounds a dimension of 6.125" to 6.13". This is incredibly frustrating as a packaging designer, where accuracy is important.
Why does this interface not honor more decimal points?