I use them because ultimately they work better than anything I've tried so far, but they're so damn expensive. They used to be only $9.95 for a box of 25, but they increased the price of the packets to $50 for 50 packets (that's like a 50% price increase) when they stopped selling the electronic agitating cleaning tub. I really liked the electronic agitating device used to clean ivisalign braces it too was expensive ($95 USD), and only lasted me about 8 months, and then it stopped working. I then ordered a new one, and I found out they stopped selling them, and in it's place they sell you 50 packets of cleaning crystals, and plastic tub that you have to manually shake yourself to ensure they get cleaned (price: $75). A HUGE rip off! I've since been using the cleaning crystals with an ultrasonic jewelry cleaner, and it seems to be working, but not as well as the original invisalign cleaning system. I usually have to run the 15 minute cleaning cycle twice to get them clean. Sometimes using diluted bleach instead of the crystal helps, but it will dull the trays. Toothpaste and a toothbrush will also dull the trays very badly.. no matter how soft the toothbrush, and non-abrasive the paste is. By the time I finish my treatment, I will have easily spent over $1000 USD on just the cleaning products, which is in addition to the initial cost of the treatment. Other cleaning agents out there that they claim work just as well... don't.