Questions on possibility of teeth moving with Essix retainer

[ana7]

Hello,

I had my braces removed about a month ago and my ortho gave me essix retainers which he asked me to put on all the time except when eating and brushing for the first 3 months.

However I have a bit of a difficulty speaking with them on, as such I do not wear them for about 9 hours a day when i'm at work. I put them on immediately after work and find that they fit perfectly well. If the essix retainers fit perfectly, does it means that my teeth have not moved since I had my braces out? And is there such thing as the gum or jaw moving but teeth are still in place?

[waterworld]

You should probably get used to wearing your retainer full time; your teeth move during the day, which puts stress on the retainer at night and could cause cracking