This could be said about more than just preaching...

“When I was in my 20’s I would read McCheyne’s Bible reading calender, and I would get some great ideas – and I would preach on it. And I do it now. And I hate to tell you: I’m a lot better preacher than I was.  And I really don’t think its a matter of exegesis skills. Its the fact that you don’t see all kinds of things in the text because you haven’t suffered. You haven’t had much experience of life. You haven’t had any major failures, where you’ve realized your a lot more sinful than you ever believed. You haven’t had major sicknesses. You haven’t suffered. You haven’t been broken. And you know, the very same exegesis skills – bible reading – that you do in your 50’s gives you all kinds of insights… And then you preach, and you’re way better than you were 30 years ago.  The real difference, I don’t think is usually exegesis or theology…its the fact that you’ve been in life, you’ve spent time with people, you’ve watched people die.”

--Tim Keller

(Thanks to Unashamed Workman for the link)