Many beginner fishermen try to utilize one rod and reel combo for all fishing situations. This is not a good idea. There are an unlimited number of scenarios that effect the proper rod, reel, and fishing line choice. Below we will discuss two common situations that relate to freshwater fishing.
Different types of lures require specific equipment combinations. Lipped crank baits that dive deep would be the perfect opportunity for a long 7 foot + heavy action rod in order to give the necessary resistance and hook setting power needed when you get a bite. A crank bait is best when fished with a baitcast reel because of their durability and high speed retrieval. When fishing a crank bait it is also a good idea to use a heavier test rated fishing line. Many fishermen use 20-25 lb test monofilament line, and some use even higher when you average in braided line which has a higher breaking strength with a smaller diameter.
If you are fishing a soft plastic bait, like a Texas rigged worm, it is a good idea to used a medium action rod with a medium weight fishing line. A medium weight fishing line would be a line with a breaking strength of between 14-20 lb. The reason for this is because any type of soft plastic lure in this category is a form of finesse fishing. When fishing a Texas rigged plastic worm you need to be able to feel the fish as it bites the lure. With the lighter fishing line it tends to be more sensitive and you feel every little bump. The reason for the medium action rod is to give you enough strength to drive the point of the hook into the fishes mouth while at the same time having enough flexibility so you don't pull the lure clean out of the fishes mouth. A medium action rod gives you a good feel when finesse fishing and enough backbone to horse that big bass out of the grass or brush and get him in the livewell.
These are just a couple of the situations the might arise that would require a fisherman to have more than one rod and reel combo in the boat. So, before you head out on your next fishing trip think about what type of fishing you plan on doing then make your rod, reel, and fishing line selection according to the type of fish you are targeting.