Personally I would change the line. The line I primarily use is not that expensive (Trilene Big Game) I buy it in a bulk spool so I always have plenty of line. Since the line I use is not that expensive and the fact that I like to change my line more often than most people because I like to have fresh line on my reels is another reason I would change it.
In your case if your reels have been stored out of direct sunlight and in a cool place then you should be fine with not changing the line. The biggest issue you will have is line memory but after a few minutes of casting and reeling the line will loose some of it's memory. If it's been stored in the heat or where direct sunlight could get to it then I would definitely change it.