Try stretching it out a little bit before using it to be honest it's inevitable for a loop to break

From Yigal Mesika:

One of my secrets to properly using Loops® is to use them at the right moment. By this I mean you use objects that are naturally accessible and have focused attention on them. For example, if you meet somebody and they hand you their business card, you can take advantage of this moment by saying, “Let me show you something interesting with your card,” and then proceed to suspend it in mid-air. This is much stronger than asking to borrow a business card and then float it. In the first scenario, the effect seems unplanned and very natural. The second scenario seems as if you are prepared to perform the trick and your magic will be less believable. You want to make your magic seem spontaneous and unprepared. I have found that people appreciate this type of magic because it feels personal to them.

There is a myth out there that if you stretch Loops® a few times before your performance, you will increase their strength. I find that this is misleading information. Stretching the Loop will definitely weaken it. I hope you do fall victim to this.

If you want to learn the real work with Loops®, I recommend the Loops® DVD by Finn Jon and myself. Also, the Inner Circle card that comes with one set of Loops and the Animated Miracles pdf. This will give you everything you need to know.

They break and sometimes at the worse time. I can't tell you how to extend their life but I see Penguin has the Million Dollar Knot in stock again. I don't know what the thread is like that comes with it but I do know that you will be able to make L**ps for pennies. The only reason to prestretch your L**p is to insure the knot you tied is good. This is the way to go. If you've bought Loops before you already have the device to keep your L**ps on. My carrying case is three playing cards joined by masking tape into which I place the original holder by folding the holder over the end card and then folding the 3 cards.