Today's tour pros change gear all the time. It didn't used to be that way, but advances in technology and big money contracts have led to top pros changing gear almost annually. Gone are the days where a tour pro would play the same irons for 10 years. Most now change with every new model year. Since the USGA changed the rules on grooves, some pros put new wedges into play every week (although they don't change wedge models that frequently).
The clubs that are changed least frequently tend to be putter and driver. The driver situation is interesting, because the driver is now one of the two or three most important clubs in the bag. Pros tend to hang onto their favorite drivers for a long time. However today's modern, thin faced drivers tend to crack under the rigors of pro use, particularly among the high-clubhead-speed players on tour.
As for some of the distances pros hit the ball, it is not unusual for big hitters like McIlroy, Woods and Dustin Johnson to hit their pitching wedges 150 yards. Golf is now undisputedly a power game, and those boys hit the ball unbelievable distances.