if you secure the ends of any seam that is not crossed by another (the crossing of seams secures them too) you should be fine- once in a while a seam will start coming un-done if it was not secured- or if prehaps you had some skipped stitches you did not catch at the time- as long as you are using a good strong thread and getting even stitches you can have some pretty long stitches still hold up just fine.