I got my braces off about 3 years ago and started wearing retainers. I wore them 24/7 for about 2 years, but the 3rd year I started to wear them only at night. Now i really don't like putting them on and I have often skipped some days and its obvious my teeth have moved because the retainer does not fit as well as it used to. Now I think I threw them away (by accident of course!) and I don't know what to do! Does it really make that big of a difference if I don't wear them anymore? How much would a replacement cost?