I use mine when I hem my dh jeans, so much easier to hem.
When I do mending, on a seam, or when I take loops or ties out of a garmet( I dislike them totally). When I am doing crafts, making bibs with ribbing, before I wash fabric, serge the raw edges, then you always know what fabric has been washed and not. When I have a towel that unravels, when, I can go on and on.....Bought mine in 94 and would buy another if needed.