I guess from trading options long ago. I can recall being correct on direction many times but ran out of time on the options. The Dec contract has options that will expire in November. The Nov options expire in a few weeks! You'd have to not only be correct in direction but very very correct in amount of the move plus see it all transpire in the next few weeks. Odds are that is not going to happen. One of the 3 won't work out which means you lose....again. Notice the Dec contract also has high open interest and similar volume and those in the Dec contract wont be worrying about the roll over coming up either. And by then most will be piling into the Dec contract. That's how I see it fwiw in any case. Nice not to have a short deadline to deal with.

Crude Oil Futures

Delivery Symbol Expiry Date Last Chg % Chg Open High Low Settle Open Int Vol
Oct 2011 /CLV1:NMX Sep 20, 2011 87.96 -1.44 -1.61% 89.18 89.78 87.00 89.40 (79239) 5.62 k
Nov 2011 /CLX1:NMX Oct 20, 2011 88.18 -1.41 -1.57% 89.34 89.93 87.22 89.59 (300180) 5.61 k
Dec 2011 /CLZ1:NMX Nov 21, 2011 88.44 -1.37 -1.53% 89.63 90.14 87.50 89.81 (191737) 5.38 k