1. probably not.
2. the lights come on when the signal from the AF sensor, in this case bank 2 sensor 1, to the ECU is outside of acceptable limits. It may not always send the same signal. If the sensor were faulty, then yes, I would expect the lights to constantly be lit. However, the sensor may not be faulty, but what we call, lazy. It all comes down to what the sensor interprets and the signal that is created.
3. it can create a situation where there is unburned fuel in the mix. The signal calls for more fuel to be added. More unburned fuel can pass through the cylinder and into the exhaust. Once in the extreme heat of the catalytic converter it is burned there instead. This will lead to a premature death of the cat. This piece of equipment is much more expensive than a sensor.
4. get it fixed since you have been experiencing this for 10 months.
Bank 2 sensor 1 is the easiest to get at. You can actually see it when standing in front of the car. It is in the exhaust between the manifold and the cat. Look between the radiator and the front of the engine, looks like a spark plug with a wire coming out of the back. Follow the wire back to its connector and unclip it carefully. Apply a little liquid wrench to the threads and wait. Apply some more and wait. Allow the liquid wrench to seap in. Use an O2 socket to get the old one out and to insert the new one.
AF or O2 sensors can be had on the interent for less money than at the stealership.
(try www.sparkplugs.com or www.oxygensensors.com), Expect to pay about $200 for a Denso sensor.
steviej
Good luck.
steviej