I know the large majority of motors used are 1.8 step, but is there any benefit to move to 0.9 step? Am going to be adding TMC2130s so wondering if 0.9 step motors are worth it
Twice the resolution on the axis… But that said, is your nozzle small enough to take full advantage. A friend of mine got a 1mm nozzle (yes 1mm) and 0.9 motors + drivers, and the smaller steps were a total waste of time lol
1.8 degrees per step means 200 steps per mm or 0.005 mm per step. If you use a tmc2130, divide that by 256. Now we are looking at 0.0000195 mm per micro step. What he heck does that mean? Well, if you imagine the build area as a grid made up of points 0.0000195 mm apart, these are the only places the extruder can start and stop. Think of it kind of like your resolution. Ask yourself if you need more precision than that. I suspect you will have much more variance in your extrusion.
The other reason for microsteps is the smoothness of movement. In general, smooth moves mean less artifacts.
Now consider slop in belts and leadscrews, as well as flex in your frame. They will introduce some loss in precision, too.
My opinion: your motor steps will NOT be the weakest link in the chain. Spend the money on quality components that keep your printer tight and true. You will notice that in your prints.