Bill Tindall, E.Tn.
I don't dry fit drawer sides any more. This short cut puts pressure on ensuring the joint is chiseled correctly.

A high spot on the end grain of a half blind socket leads to a joint that will not close and extra planing of the side when drawer fitting. I don't like seeing joint gaps when opening a drawer.

I check for high spots on the end grain and long grain by setting a 4" square to the length of the tails and then rubbing the square in the socket. The square will hang up if the back wall has a protrusion. The square leaves a burnish mark on the long grain, visible in the picture. I want to see this burnish line at the edge of the socket where the side will mate tightly.

Not for everyone, but I oversaw the pin slightly, but not near as much as I see on some antiques. Presentation grade dovetails have never been a goal for me. It makes getting the corner waste out easier. There is something about getting these fibers out that I find annoying. I strive to make it easier.