I assume you mean LED.

3" , 4" and 5" diameter are standard in residences. These are nominal sizes so the actual size is a bit different.

I usually use recessed lights when I don't want the light source to be obvious so I use the 3" fixtures which are actually about 3 1/2".

Unusually tall ceilings might require an output of 800 lumens or higher or a commercial grade recessed light.

There is no point in asking an architect what others might use.

Our standard spec is a 5-6" recessed housing with a 2700-3000K 1100 lumen LED trim. Typically these are in 10-12" ceilings. The 4" recessed have lower output, but are less obtrusive.

The 4 in are fine in 10 foot ceilings. Spaced slightly closer together but IMO very good (ie high) output.