From my everyday experience and observation I have to agree with the statement that our present experiences become valuable lessons for the future. Someone said that today's problems will be the best experience in the future. Below I will give some examples to support my position.
First of all, I want to say that obstacles make people stronger. By overcoming difficulties people gain priceless and essential knowledge and experience. If one has to struggle with a disease he becomes stronger may be not in a physical way but in a mental way. A person becomes more patient, more self-confident and more attentive. These qualities will help him to win his disease.
Success has nothing to do with luck. People have to work hard in order to reach their goals. They face challenges and failures and often they lose. However, people do not give up. They use their previous experience and knowledge to try again and again. I think that difficulties teach us very valuable lessons. Only a man who understands this fact and knows how to use it in the future can succeed. Failures bring us wisdom and new experience. Personally, I always try to analyze my mistakes and make conclusions. If I am not succeed I know that next time I will avoid these mistakes and do my best.
To sum up, I think that human evolution and development are a result of constant efforts based on previous experience and knowledge.