There was a friend (girl) who wore a retainer some time ago. She wore her retainer only at nighttime, but during the weekend she wore it during the day (mostly at home), because she don't want to be seen in retainer when clubbing around.
Some times she wore it daytime (even outside home) also because her mom bothered her about not wearing it enough, and she has a big lisp because she was not used to talk with the retainer in.
Many years ago, instead, a god friend wore it's removable appliance only at school, because his parents told to the teachers about it. But he always "forgot" to wear it at home during sleep time...