I think there is a little confusion regarding ignition switch vs. the actual lock cylinder used on the steering column. The ignition switch is a set of electrical contacts that are mechanically connected to, but not a part of, the lock cylinder. The locksmith was being quite vague in saying the "ignition switch."
Have I ever heard of a lock cylinder failing? Not in recent memory. But I've had two ignition switches go bad on me--one in my '97 CR-V, the other in a '99 TL. Both had recalls by Honda, and both were easily replace by me for about $35 in parts. (They were in the steering column on the opposite side of the lock cylinder, connected by a flat metal rod that rotated the switch.)
Similar to what
@Traylaw says above, you may hear a buzzing in the switch when it is starting to fail. Or in my case, the vehicle would shut off while driving, like someone had reached over and turned the key off. Fortunately they always started right up afterwards, but I made sure to order in a new switch and replace it as soon as I could.
Both of our '09s have had zero issues with the lock cylinders and ignition switches. Both have around 150k miles. To maintain the lock cylinder, follow
@Carbuff2's advice and get some dry graphite lubricant to keep the tumbler pins moving freely. (Never use an oil, a spray, WD40, etc., in any lock cylinder--they will gum up and attract dirt. Graphite is a dry lubricant that does not attract dust and dirt.)