For those not familiar with the terms, see the link.

The basic rule is that for flat light coloured paints with ordinary lighting conditions, Level 4 is acceptable. That is the standard, in fact, where I build. However, in other areas, Level 5 is the usual standard.

For semi-gloss, gloss and dark paints, you must use Level 5, otherwise the joints and screw hole repairs will be visible.

I build higher-end homes and find Level 4 finished by a good crew to be acceptable, even for mid-range satin finishes. However, keep in mind that many of the walls are eventually covered with other materials and finishes, such as wainscotting, faux and textured finishes, cabinetry, paneling, plaster ornamentation and stone. Sometimes I find myself doing a lot of fiddling with lighting to keep it from shining directly on the walls, revealing the seams etc.

Experienced tapers and painters can spot imperfections the usual person, including me, would never see. Buyers as a rule are forever more concerned with some little speck in the drywall than structural matters.

Here is a link that might be useful: Drywall Finishing Levels.

Interesting! I didn't know there were formal ratings for sheet rock finish.

My hangers do a fair job, but it's cost effective to do touch up myself. I'm a one man band, and a bit of a perfectionist, so I cause my own share of dings anyway.

Buyers? Hah! They wouldn't care if the front door was made of OSB as long as it had a Baldwin lockset.