Fit: These are patterned from an original WWII Boot which run a half size larger than modern ones. Thus, if you wear a half size, order down, not up. For example, if you wear a 10.5, order a 10.
Width: Although they are marked "D", all of our boots are made on an "E" (wide) last. If you have extra narrow feet, an insole and thicker socks may work. For extra wide feet you can try going up a size. Most people have honestly been able to find something that fits. There have been far fewer problems with this sizing than I had anticipated.
Returns: Used boots are not returnable, except in cases of product failure. (Sole falls off, eyelets out, etc). Try them on in the house and walk around the living room and be sure they fit before polishing, sealing or wearing them in the field.
Squeaks: Some of these boots squeak when new. For the uninitiated, that's not a diabolical plan on our part to alert German snipers to your presence. It's a fact of life with leather boots and shoes. It will normally work itself out as they break in. My Corcorans squeaked when I first got them in the Army. (The real Army...) If your boots have not been worn, you may return them. If the boots are worn, a squeak is not a defect warranting replacement. It's not a defect. It's leather. Someday we'll see about getting custom-made-squeak-free vinyl boots made...