I can't say with an older bow, but with a newer bow it is fairly rare to have to change limbs. If your shop is doing it a lot I think something may be wrong. I have a friend that has a 13 year old darton set at 72 lbs, still has the orignal limbs on it with no problems. Every now and then you get a new bow that will have a cracked limb or something and need replaced, but it is not the norm and should be a rarity. In most cases from what I am seeing on these boards it is due to improperly pressing these style bows with short limbs. If your shop is having problems with limbs on newer bows maybe they are doing something wrong. Limbs should pretty much last the lifetime of the bow.

As far as turning your poundage up and down, you don't really need to. And really shouldn't with the set up you have. Because of what I described in my last post about the arrow having to flex and snake around the riser (archers paradox) you need the properly spined arrows. One of the main things that effects spine is the draw weight of the bow. There is no way you could shoot that bow at 20 or 30 lbs and then turn it up to 60 or so and have it tuned correctly. The arrows would either be severly over or underspined at one of the settings. You would need different arrows for each setting in order for it to work correctly. And man that is a lot of draw weight range! Most new bows are only adjustable for around 10 lbs. Like if you get a bow with a peak weight of 60 lbs you can only turn it down to 50 lbs. You might get a few lbs less then that, but not much more than that in most cases. I think martins have a larger draw weight range, maybe 15 lbs or so.

You should find a draw weight that is comfortable for you to shoot and stick with it year round. Unless you are going to shoot spots where you will be shooting a lot in one session and will get tired. But often when you change anything on your set up your bow may need to be retuned. Everything effects everthing else to a certain extent.

I think you need to find a shop with some experience with older set ups and pick thier brains some. I will see if I can get you some help here. Someone with more knowledge than I have. None of what I am telling you is from personal experience, just from what I have learned from other people and research I have done. All my experience shooting and tuning is with newer style coumpound bows. The oldest bow I have messed with would be that 13 year old darton maverick I was talking about earlier. And I am not a professional bow mechanic or anything, I just shoot and play alot and spend way too much on sites like this reading information and talking to others.

I think once you get some of these issues straightened out with your bow and arrows you should shoot a little better. Providing you have good form and release. 90 percent of archery is mental any way.

Good luck,
Paul