Characters are usually approved in 24 hours (at least that's the norm) though it's important to remember a few things.
1. People volunteer their time to approve characters thus they'll schedule their "approving" when all of their real life work is done (meaning you probably won't see a ton of characters approved during the middle of the day).
2. A larger bio can be tedious to read (I know because I write them) and as a character approver you have to pay special attention to every little detail so that you don't accidentally approve someone with dragon blood. So that's another reason people might not approve characters every day. You need to have a good chunk of time to commit to one bio.
3. Last, the approvers are players also. Meaning that in that free period between work, school and sleep, they'll not only want to approve characters but play as well.
So yeah. To answer your question, 24 hours is most common. 48 is not unheard of though (in busy times such as these). If it goes into 72+ hours they either completely missed your bio, are seriously seriously swamped, or are discussing it in the GM Forum before approving it. Fear not, ye shall gain entry to the wonderful world of Layonara soon enough!
