If rollouts to the following year are needed, you might think you would have to pay to go down to the next strike but you would be wrong.
Right now for example if you have the 15-strikes for INTC expiring in Jan. 2012, they are quoted at $29 bid, $31 asked. If you wanted to roll to the 12.50's for Jan. 2013, those are now at 449 bid, $55 asked. So the worst you would do would be to buy back the 2012's for $31 asked per contract and then sell the 2013's for $49 bid per contract. That's $18 per contract and if you were rolling 100 contracts, you would actually receive $1,800 in cash before about $200 in commissions - or about $1,600 net.
The individual prices would be higher if the stock were to tank but the differential would in all likelihood be even GREATER than $18 per contract and that's money in your pocket.