All of my leather products are hand stitched by me. Everything is double stitched (saddle stitched) using one length of thread with a needle on each end, this means each stitch is locked into place.
Hand stitching is much stronger than machine stitching. A machine stitch keeps each stitch on the same side and interlocks each thread in the hole meaning if one stitch fails then all stitches can unravel. This isn't the case with hand stitching, as every stitch is locked individually. Even if one stitch is damaged then the rest of the stitches will remain intact.
All of the thread I use is hand waxed by me using beeswax, this provides extra hold to ensure all stitches are tight and will stay in place.