Originally Posted by skltlf
never with a bluff! lol
Actually it's usually a smaller mistake to bluff too large than it is to bluff too small.
Take an example where we have the nut low in a $100 pot and our opponent checks to us on the river. We think he'll fold 50% of the time if we bet 1/2 pot ($50), 75% if we bet pot ($100), and 80% if we bet $200. The EV for each bet is:
1/2 pot - $25
pot - $50
2xpot - $40
So while it's a mistake to bet $200 here it's less of a mistake than betting $50.