Most of the price of a machined part is machine time, and tight tolerances add time: slower cuts, extra finishing passes, more inspection (sample note).
Hold the tight figures for the features that fit something: bearing bores, sealing faces, locating holes. A general tolerance of plus or minus 0.1 mm is easy for every machine on our floor.
If you are not sure which features matter, send the drawing anyway. Our estimators mark the features that drive the price and suggest where a looser figure would save money.