LOVE! I got this for my daughter's 4th birthday [SEP] LOVE!  I got this for my daughter's 4th birthday, but who am I kidding, I got it for me!  First I did 1 coat of each color just to try it out.  It definitely needs 2-3 coats.  The 1 coat didn't last very long, so I've been doing 1-2 coats of clear also.  It DOES work when clear polish is over it.  I can see a change in every color.  Usually my feet are the cold color, and my fingers are the hot color.  LOVE this stuff!!!!!