Throughout my flight training, there was always emphasis on filing a flight plan, opening a flight plan and closing. This always puzzled me. So, I would like to get some information from experienced flyers. First, where can I find the current frequencies and telephone numbers for the various Flight Service Stations? Next, as I understand it, the only purpose a Flight Plan serves, is too alert authorities when an aircraft is overdue, often assuming an off airport landing in some deep wilderness area. But if flying around moderately populated areas (as most of us do), what's the point? Someone will see it and call 911. And lastly, do veteran GA pilots always file a flight plan? Or is that now considered largely unnecessary, except for training and initial certification, and for long distance flights over sparsely populated areas?