Technically, the Lagrange point is just that -- a point. Spacecraft don't actually occupy the true Lagrange points. Instead, they orbit them in what's referred to as a "halo orbit". If I recall correctly, SOHO takes almost a month to go around the Sun-Earth L1 point.<br /><br />Crowding could eventually become an issue, although in the forseeable future there aren't enough Lagrange spacecraft planned to be a real problem. All spacecraft at L1 and L2 have to have propulsion systems (the points are unstable, so they have to fine tune their orbits on a regular basis). So when they reach the ends of their missions, I would hope that mission planners would move them into a long-term storage orbit. Even if they don't, though, the dead spacecraft will drift away from the Lagrange point over time, which helps a bit with the problem.<br /><br />L4 and L5 are a different matter. These are stable points. In fact, there are natural satellites in other L4 and L5 points, such as the Sun-Jupiter ones. They're called Trojan companions (named for the class of asteroids orbiting in the vicinity of the Sun-Jupiter L4 and L5 positions). Spacecraft should be moved off of them somehow at the ends of their operational lives, although given the nature of L4 and L5, this may require a substantial investment of delta-vee. There are no spacecraft currently planned for these positions anyway, though. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>