“One thorn of experience is worth a whole wilderness of warning.” – James Russell Lowell
People like to give advice and warn you about things. People think this will help to set you up for success and make you better prepared for the experiences to come. However, this is not usually the case.
You cannot replace or replicate the personal experience. You and you alone will experience something in your own unique way. Even if you go back to recreate the experience, it will never be the same.
I think what James Lowell is saying here is that nothing compares to the first-hand experience. Even if you have heard about it from a million people, it will never be the same as experiencing it for yourself. So, while information and sharing your past with others is nice, it will never be worth as much as one thorn of experience.