Why Do I Have to Wear my Invisalign Every 6 Weeks? The Standard Seems to Be Every 2 Weeks.

6 weeks seems a bit strange. The material in the aligners is designed to apply a prescribed force for 2 weeks, assuming ~22hours of wear per day.

Sometimes your doctor might add in an extra week of wear for you if he thinks perhaps there are a few more hours of wear you 'll need out of that set of aligners to catch you up for your next set of trays, but beyond 3 weeks the aligners are almost entirely worn out. In fact, many times if one dental arch is treated faster than the other, your orthodontist will build into your ClinChek sets of passive aligners for the completed arch to hold those teeth while the other arch continues to move. I have seen teeth move backwards inside worn out aligners because they have become overly flexible.

In my office almost every patient wears their trays for 2 weeks.  I am not sure why your would have to wear them for 6 weeks movements normally occur in the 2 weeks and not much occurs afterward.  I would discuss it with your dentist

The standard wear times for each aligner may vary from 1 week to 3 weeks, with 2 being for the majority of patients.  This is going to depend on the amount of movement, type of movement, and time/day the aligner is being worn. 

That being said, 6 weeks per aligner may be slightly long, as the aligner plastic may lose its ability to keep shape following this type of interval.

Again, speak to your doctor to figure out why your plan involves 6 weeks of wear per aligner.  Good luck!