The very first thing is that a well maintained vehicle would utilize less fuel which means your fuel cost would get reduced. If the ATV parts have been replaced from time to time then no other part of the vehicle would get damaged. This might be hard for you to understand straight away. Well take shocks for example. In an off road vehicle like an ATV, shocks are very much important. If they are not working at their best you would need to replace them as soon as possible. If you would not do that then the tires would get damaged as well. Not to mention your back would start to ache due to the bumps. Everyone knows how much tiresome an uncomfortable ride be. If you are well in touch with the market then you would know the cost of new sets of tires as well. For this reason you must always install brand new ATV parts, not the second hand ones.
If you are so keen on purchasing second hand ATV parts then purchase body parts, side view mirrors and other accessories. Just put a little more money on these parts and they would look as good as new. Use this saved money on purchasing brand new performance parts for you vehicle.