How long is overnight? 8 hours?

It can depend on the recipe. What you should do (now and in the future), is determine why it is sitting in the fridge in the first place. In the case of biscuits, you want the butter to be cold and hard so that it doesn't mix into the rest of the dough. That way, the butter steams up and assists the baking powder in leavening. It helps create a layered, flaky biscuit. Honestly, I would tell you that you would be fine with 2-4 hours in this case.

Other recipes may require longer rest periods, like in the case of some yeast bread doughs as mentioned above. Other things just get better the longer they hang out in the refrigeration and, again, the choice is up to you. The best thing is to know WHY it needs to sit in the fridge and you can determine exactly how important the amount of time is.

A lot of recipes say overnight for bread because they want the gluten to relax. Allow an joe in the fridge , proof and bake as you otherwise would.

Thank you all. In sum: it does not have to be "overnight" really--just 7 to 12 hours, e.g., from 7 am to 7 pm or vice versa. Makes sense to me.

From the time you put it in the fridge until the next day.

I think of "overnight" as being at least 7 hours, and up to 12.

Cookbookchick: Thank you.

Eight hours should be fine.