When evaluating leather sole shoes, prioritize the construction method, with Goodyear Welted or Blake Stitch being the industry standards for durability and resolability. The upper material should ideally be Full-Grain Leather for maximum longevity and breathability. For the sole itself, ensure it is made of high-density vegetable-tanned leather to provide proper arch support and moisture absorption. Additionally, check for cork filling in the midsole, which allows the shoe to mold to the wearer's foot over time.