Retainers are worn after the braces come off to “retain” your straight teeth.  Without them, your teeth can drift back into their original position.  When your braces come off, the peridontal ligaments are stretched a bit and after wearing the retainers for a year, they go back to their original state.  That’s why its so important to wear your retainers 24/7 for about a year.  After that, you can just wear them at night.  Nowadays, we tell our patients to wear their retainers indefinitely.  Relapse (teeth shifting back) can even happen in your 40’s and 50’s!  After a few years of consistantly wearing your retainer, try it in at least once a week.  If it feels tight, chances are your teeth are trying to shift and a good sign that you need to wear it more often.