Essix retainer question

[KUMonkeyMomma]

I have 2 really small splits in my essix retainer (top) - and I had this same issue with some of my aligners as well. I called about getting a new one and am waiting for a call back - I'm assuming they can use my molds from when I finished treatment to make new ones.

I'm wondering if essix retainers stretch out over time? I worry that the new one will be really tight.

I've noticed that one tooth has moved a bit (it was one of my more troublesome teeth to move), but not enough that the retainer does not fit, etc. My retainer is snug at night when I put it in and then is loosened up by morning (similar to when I would put an aligner in after it being out an hour for a meal, etc). So I'm guessing that my teeth move a bit during the day and then get pushed back into place at night, so I worry that if my current one has stretched a bit in the 3-4 months I've worn it that the new one will be too tight or not fit, etc.

How often should these be replaced? I have read some say they last years and some say replace every 4-5 months, which is a huge difference. I spent a lot of time and money to get my teeth the way they are - and they still aren't perfect due to an overbite (my upper jaw is physically larger, and the top teeth could only be moved back so far - it would have been the same with metal braces) so I definitely want to keep them where they are as I'm happy with the result and they look 100% better than they did before I started (overbite and overjet, crooked, one tooth partially behind another, etc).

I thought about asking for permanent bonded retainers on the top (the bottom retainer fits fine and those were mostly good to begin with so didn't require much movement) - is this something I should consider?

[TumbleDryLow]

I don't think the retainers stretch over time. If they did, they wouldn't be very good at retaining, would they?

Molds are usually destroyed in the process of making the retainer so new molds will need to be made. The new retainers should not be any tighter then the old ones. If you have issues with one or two teeth, address them with the ortho. Essex retainers can be made to do minor adjustments.

Retainers only need to be replaced if they are damaged. I don't know if there are different thicknesses/qualities of Essex retainers out there, but mine look as good as the day they were made. I've had mine for a year. Half of that year I spent 24/7 in the retainers and the other half the year I spent 12 hours in them. So they have been put through some serous wear.