The secret is the welt. Goodyear- and stitchdown-welted boots (Red Wing, Thorogood, Danner, Wolverine 1000 Mile) are built so a cobbler can stitch on a fresh sole for a fraction of the price of new boots. Cheap cemented (glued) boots can't be resoled and last 1–2 years. Condition the leather a few times a year, resole when the tread's gone, and a good pair goes the distance.