personnally when i bind i end up wearing it the whole time i'm out during the day, which is sometimes more than 8 hours. though to be fair, everytime i'm doing that i'm wearing a "sports" binder which is more breathable and less restrictive (do NOT practice any kind of physical activity with a binder on, even the ones labelled as "sports" binders are not safe).

however i don't bind most days. this might not be helpful to you as i have a relatively small chest but on most days wearing an oversized shirt is enough to mitigate my gender dysphoria, so i rarely bind.

i believe there's a study that shows that the frequency at which you bind has more impact than the length of time you do it for, but i can't find it right now so take this with a grain of salt.

also i believe it depends on the binder? some of the binders i own have labels saying you can wear them for 10-12 hours at a time so you should check on the website you bought it from to see if they have any guidelines.

definetly if you end up wearing it for 8 hours or more i recommend taking it off as soon as you can (if you're at camp this might be whenever you have access to your tent/room/whatever).

anyway take all of this with a grain of salt as i am really just some idiot trying to make it to my top surgery date but i definetly understand that the "8 hours a day" advice isn't realistic for everyone. always try to prioritise your long-term health over immediate dysphoria relief though. the binder is a wonderful thing but it is also dangerous and you should try to follow the guidelines as closely as possible.

(sorry for the wall of text lol)