Probation lasts until the person or people who put the person on probation agree to end it. This usually means either a deal which did not go through finally went through, a compromise acceptable to the probationer has been reached, a good reason for why the deal had to fall through was given, or the probationer realizes they made a mistake. So potentially probation can last as long as the boards themselves last, as long as the very Earth that houses these boards lasts, as long as the very galaxy that houses that Earth lasts, as long as the ...
So a light toasting is not in order? Come on - a little singe here and there. Promise, it won't hurt. The tribe is ready for this big event.