I did 2.5 years of Invisalign treatment, and 1 year of retainer (so total 3.5 years since I started).My dentist told me that for a small fee (about 300 dollars), he can do one more round of scan and get me more trays to last me until the end of 5 years. I kind of just want to finish the treatment now and be done with. So I'm leaning toward just get the Vivera retainer. But it seems like a good deal to get more trays for just a bit of money.So I'm curious, do most people keep on getting refinements until the end of 5 year period?