I did one last year when they allowed formaldehyde and it was awesome, lasted 8 months! No need to blow dry at all. They have since regulated it so the actual working (yet unhealthy) chemical is now no longer in the formula. I can say that it does help me have straighter hair, but I do need to blow dry it each day unlike last time. Do I thin it is worth 200 quid? No. But if you can get a deal I would try it out. That said, it does depend on your hair and what you are looking for as an end result. I will not be getting it done again, I think the price is too steep for the results I get. I might try the straightening at home kits. If anyone knows any place that still uses the formula with formaldehyde though, let me know - I would gladly pay the price for the potential health risk (to the client and the others in the salon).