All springs take a set if left compressed over time. The question is how much of a "set" can a spring take and still function as designed. The other variable is the quality of the spring. Wolf springs are the best made, and the fact that there are companies that only make springs should tell you something about spring life. I had a .22 rifle fail because it was left cocked for several years, unbeknownst to me until I took it out to shoot. The bolt spring was a coil spring, like in your car suspension, and we all know these become weak after years of sitting around with the weight of the car compressing them, not from use, since a car spends most of it's life just sitting around. The same thing happens to magazine springs left compressed. This is an age old discussion where many people, by virtue of the fact that their mag springs still work after being left loaded for years, will CLAIM that compression doesn't hurt. This is complete BS and runs counter to not only common sense, but metallurgy. Also, stretching a spring in the opposite direction from compression actually weakens it further - it will strengthen the compressive strength temporarily for a very short period of time, and this may be a good thing for a battle scenario, but ultimately a spring which has lost it's tension will need to be replaced. It always amazes me that any kid with a wind-up toy knows this, yet adults who spend hundreds of dollars on their "toys" just don't get it...