Maybe I'm not a very technically sound rider - I find that when I am climbing ( i live in the ozarks) I often need to change gears when i'm out of the saddle, I have to sit down to change gears as I can't be out of the saddle and safely reach my downtube shifters.

I always wondered how the pro's can be out of the saddle climbing/sprinting and change gears on the fly on a down tube shifter.

I'm running 20 year old Suntour system right now - I love it except for this issue.