Please specifiy total poi length, including head and handle.
General Notes on Tether Care and Lifespan:
SpinOptic Tethers are covered under warranty for defects, but not against wear and tear. Generally speaking, the fiberoptic tethers are more fragile than normal tether material, and need to be treated with more care. They are a consumable item, and we think of them like guitar strings: they'll need to be replaced occasionally, but the lifespan will depend on your play style.
Here are some general tips for tether care:
The first and most important thing you can do to improve tether life is to never pull the LED module back into the head by the tether after changing the battery. Instead: always push them back in by their tailcap.
Wraps are fine, but you need to use the softer rebound technique. There are two general ways of doing wraps:
Hard, with a firm/aggressive return impulse. Where you forcefully jam your hands in the opposite direction just before the innermost moment of the wrap. To tell if you're doing it this way, just ask yourself if the wrap feels like a "Slam". This will generally shorten tether life due to the higher forces involved at the root of the tether.
Soft, with an absorb/return impulse. Where you briefly wind your hand(s) in the same direction as the rotation to softly catch the head(s) just as the wrap reaches its innermost moment.
If you do wraps like method (2), you may find that your tethers stay healthier, longer.
Orbitals are a nono, since there aren't swivels at the handles (there can't be for the light to make it all the way into the Pom/Ovo grip) if you do an orbital, you'll be twisting the tether at the handle and that can definitely shorten its life at the handle, but probably won't affect its brightness. Hyperloops, on the other hand, are fine...just don't yank on the handles when you do them and they won't actually experience much stress, if any.
Likewise, tangles should be fine, as long as you aren't yanking hard.
Some people like their tethers to be as straight as possible, and don't like when they get plastically bent, and you can help avoid this by hanging the poi by the handles on a rack when you aren't using them.
Always store the tethers away from direct sunlight. Sunlight is bad for most plastic and causes it to yellow over time. This will decrease brightness because the tinted plastic absorbs the light before it can make it out. Just make sure not to leave the poi hanging around places where the sun will shine directly on them; always keep something between them and the sun. It's easy to leave poi hanging out of a backpack or on the seat of a car when you go to a festival, or next to a window in your spinning space, and this is where it happens.