I have had an Elnita Lock since 1986 (or so) and it has served every purpose I set in front of it==including letting my sister use it and she crammed too much material into it and bent the under needle (whatever it is called) and all I did was straighten it out to what I thought it originally looked like, and it took off again. Now, I am the only one who uses my serger--some people just don't understand the principles of a serger, so I do any sergeing (looks funny, huh) that is done in my sewing room. I have to have the knife sharpened periodically, but I have someone nearby who knows how to take it off, sharpen, and replace it. Mine has a three color thread guide path, easy-peasy (I've seen that on this forum before); set your tension guides to zero, knot off your thread changes (just as if you were knotting your sewing thread for a needle and hand sewing); make sure you pull them through before your put your tension numbers back in your tension guides. And NEVER pul a knot through your upper needle, it'll bend it. And if you are a slow sewer, learn to sew fast, because speed is absolutely necessary with a serger==wide open is best. Good luck to ya.....