I am sure I will not have many racers agree with me on this post. We would joke around about asking the customer what he was doing when a component failed. The customer would reply "racing" and we would answer “well, there’s your problem”. Not that funny to the customer with broken parts, I guess. My point is racing is hard on parts. Most would agree on that.
Years ago, racing valve train components had many problems. Valve springs were manufactured with inferior steel and camshafts were bad copies of other camshafts. Some cam profiles had been copied many times, so the errors just added up. The combination of these camshafts and springs in a racing engine was a problem waiting to happen. The quality of flat tappet lifters was inconsistent. The crown and edge chamfer on the lifter face was the problem. This would sometimes cause the camshaft lobe to wear and of course the camshaft grinder was blamed. Roller lifters also had their problems. Especially when used on small base circle camshafts. This creates too high of a pressure angle. Unfortunately, it is still a problem today. Pushrods were tubes with ball ends welded on. Not very strong. Roller rocker arms were fairly decent, but still had their share of problems.
Today, the quality of components is the best they have ever been. There is junk out there and that is what you must avoid. If you are going racing, any racing, you better buy the best parts that are available. Many racers do not do this. Racing is an addiction, just like drugs. Many do it even though they can not afford it. This causes them to buy the junk parts or parts that are not as strong as they need to be for the application. The results are obvious, broken parts.
Sometimes a particular rule will force the racer to use components not up to the task. Unless you ignore the rule, the results are broken parts. All components wear out and break. They must be replaced before this happens. This can get expensive, so many do not do it. The results are broken parts. If components are continually failing, there is more than likely a problem on your end, not the components.
If you want to get in to this sport, realize it will take all your money and may not give you anything in return. Just as bad or worse than that pretty girl at the mall. There should be some kind of agreement to sign in order to be a racer. That may stop some of the whining. If money is a problem, do not get in this sport. If you do anyway, accept the consequences. As the saying goes “the truth hurts”.
In summary, parts are high quality today. If they are used correctly and in the environment they were designed for, the chances of having a failure are low. They must also be replaced on some type of schedule. Always analyze what you are doing before immediately blaming the part.