When I make pintos i soak them for at least 2 hours, but I pressure cook them. I made some for my Pathfinder game late Sunday, i soaked for 20 hours. They came out perfect. I also add baking soda to help break down the protein shell, i mostly do this with older beans.

These were beans that I canned. So it was a overnight soak, change out the water, 30 minute boil, skim off the top, put into jars, can for 75 minutes which also finished cooking them.

For beans I'm using immediately instead of canning I typically do either an overnight so or a 1 hour soak after boiling for 5 minutes. Then I will change out the water and boil for 1 to 1 and 1/2 hours depending on the bean and desired tenderness.