[Rupert]

I use the old "about 7 days", rolling 1d6, with the jump taking 6 days on a 1, 8 days on a 6, otherwise, 7 days. Many misjumps take 6-10 days instead.

You can tell when you'll come out until a few hours beforehand, and the exact emergence time is only knowable a few minutes prior to emergence. One of the first signs of many misjumps is the jump bubble starting to decay early or emergence not occurring until after 8 days.