It depends on how you are going to fish for Crappie, trolling needs a stiff rod with a line counter reel, spider rigging you need 11 or 12 foot rods and small spinning reels so you can spread out your baits and vary the depths, shooting docks you need a 6 foot rod with a good reel that feeds out line easily, casting jigs takes an ultra lite rod to cast light weight baits. So you see you can never have too many rods or reels to fish for Crappie. The more the better.(at least that is what I keep telling my wife)
Dave