The sashes, the parts you move up and down, are supposed to hang in space without any friction. That means they should move with very little effort, and stay where they are put. There should be at least 1/8" clearance all around, side to side and in and out, when open. The only time they should be tight is when closed, at which point the "bump-out" feature should push the bottom sash against the stops (when the window is closed, and the middle rails meet properly, they are pushed apart a little). When opened, there may be rattling in windy conditions because of this construction, unless there is weatherstripping installed.

People tend to assume the old windows are faulty when they rattle in the wind. But this is simply a result of the design. If they rattle when closed, that is the result of improper alignment of the components.