I cherished my first hunting bow. When I bought it, I was still in school and had an extremely limited budget. That bow was my companion in the woods for years and years. As it aged, I nursed it along until I could finally afford a new one.
When I bought my second bow, I held onto the first one, mostly for sentimental reasons but also to use it as a backup. I left it fully set up with sight, arrow rest and quiver. I shot it occasionally to keep the moving parts moving. I still have that old bow.
I still do the same thing today. As I upgrade to a new bow, I always keep my most recent bow as a backup. The obvious reason is to use the old bow if my primary bow breaks down. However, there is another important function of a backup bow.
Is Newer Better?
Your new bow will be just that — new to you. You will not be familiar with its feel. Occasionally, you may get a bow that just doesn't shoot well for you. Most archers will blame themselves for the poor performance. However, if you pick up your old bow and find you shoot it well, you may need to take a hard look at your new bow and find out why it is not performing.
The problem may be defective accessories, a poor tune or something inherently wrong with the bow itself. And keep in mind that sometimes a good bow and a good archer just don't get along; something in the geometry of the bow clashes with the shooting form of the archer. If that's the case, and you've put considerable effort into adapting to the new bow without success, you may want to trade it in on a different model.
Occasionally, we all go into a shooting slump. We just don't seem to be able to group our arrows well. Most often you'll find it is just human variability or a downturn in your biological rhythm. I always try to blame my equipment last — after I've made sure my form is at peak performance. However, it may be there actually is something wrong with your bow. The best way to figure out if the trouble is with you or the bow is to pull out your backup bow. Your old bow will serve as the control in your experiment. If you can shoot great with your backup bow but not with your new bow, then you need to start troubleshooting your new bow to see what is going on.
Some hunters have more than one bow for different reasons. They will use one bow to hunt deer-sized game and another bow to hunt bigger game such as moose. If you like to hunt different species, such as elk in September and then whitetail deer in November, should you have two different bows? After all, gun hunters often have more than one rifle. They might use a .243 to hunt deer and a .300 magnum to hunt elk.
I have a strong opinion on this matter, at least when it comes to archery hunting. Shooting the same bow throughout the summer and then through the entire hunting season improves your odds of making a good shot when the time comes. Muscle memory is extremely important in archery. Each practice shot helps fine-tune your body to execute the shot subconsciously and flawlessly. However, your muscle memory is being fine-tuned to one geometry and one draw weight.
Switching back and forth between bows will confuse your body and lead to inconsistencies. This will become most evident under the intense pressure of shooting at game. When you aren't really thinking clearly, you want your body to go on auto pilot. It is relatively easy to shoot a 60-pound bow and then a 75-pound bow well in your backyard, on flat ground and with no pressure. However, the bows will behave differently as your form deteriorates under adverse environmental conditions and in high-pressure situations.
Gun hunters have the luxury of just putting the crosshairs on what they want to hit. Assuming they have a good rest, all they have to do is squeeze the trigger, whether they are shooting a BB gun or a .378 Weatherby Magnum. The guns behave fairly independent of the shooter. A gun will hit the same spot when shot by two different marksmen.
Bows are different. They require a great deal of muscular involvement to execute a perfect shot. Shooting a bow is a dynamic activity. Each bow will shoot differently for every individual archer, and each archer will shoot the same two bows differently. How a bow shoots depends on the holding weight, axle-to-axle length and a variety of other factors.
If you are going to hunt deer-sized game and very large game you may want to consider using a heavy arrow with a smaller diameter (better penetrating) broadhead for large animals and then a light arrow with a larger cutting diameter broadhead for smaller animals. This way you can use the same bow for all game. Your body will not know which arrow you are shooting, only that the bow is the same.
Personally, I use the same exact setup for everything I hunt. That wasn't the case before the advent of laser rangefinders. Back then, I shot a very light arrow for long-range game such as mule deer and antelope and a heavy arrow for elk. But now I shoot a relatively heavy arrow for everything. It keeps my bow quiet and it provides great penetration. I used to like a heavy arrow for elk and a lighter, faster arrow for longer shots at deer and antelope because of the ranging errors I might make. But thanks to the rangefinder, I am no longer so concerned with arrow speed.
Using the same rig for all hunts keeps things simple. You will always be intimately familiar with your equipment, and the confidence that familiarity brings will make you more successful in the field.