Often times we are too excited about a particular leather bag or item to take the time to look at the small details. We overlook all the important things that would intern change our level of excitement. The quality of thread and stitch work is one of such things.
Some threads are generic like what would be used on a generic white t-shirt. These generic threads are often used in leather bag making and aren’t capable of handling your intended payload. Some threads are made for industrial uses and will last a good chunk of time. These threads are easy to notice because of their irregular thickness and make for the best durability in a genuine leather bag.
Now keep in mind, the sewing handiwork also plays a large role as well. Loose threads hanging off on every edge clearly constitutes as poor sewing. Some of these threads can easily be gently tugged unraveling the entire seam, and often times unravel themselves without any help. So, paying attention to the quality of thread and stitch work could determine how often you need to have your leather bag resewn or possibly even replaced.