For me, personal experience is a significant part of the research process for writing, whether fiction or non-fiction. I certainly do as much research outside of my personal experience as I do inside it, but I've come to think that introspection based on personal experience is a useful tool for certain kinds of stories. I tend to write stories that are heavily character-based, and using personal experience to get inside the head, or the heart and soul, of characters seems to work for me. Of course you use bits and pieces from all over the place to do that, and the characters might incorporate elements from a dozen different sources that seem to blend into something worthwhile. That doesn't mean I think personal experience is for every writer.
Different people go about writing in different ways.
You have a reputation in the field for your speculative baseball stories, many of which are collected in Where Garagiola Waits . For me, baseball is so firmly embedded in the family tradition that it's sort of inescapable. He spent his whole life in the game, and so of course his family did, too. I have very firm memories of hanging out in the clubhouse and dugout at Fenway Park, for instance, and then of being the batboy in minor-league towns like Charleston, West Virginia. It was a great childhood, spending six weeks each spring in Florida for spring training, having family friends like Stan Musial and Joe Garagiola and the like.