Poke Test
As an additional precaution, you can use something artisan bakers call the "poke test" to see if the dough is fully ready. Poke the dough about 1/2in deep with a floured finger. After you remove your finger:
If the indent slowly springs back or doesn’t recover at all, the loaf is ready to go in the oven.
If it springs back right away, you can give it more time, but no more than 3 hours total. If you are running short on time, don't worry, you can cut the proof short. Your loaf may not rise as high but it will still be delicious.