What factors influence the stability of planetary orbits within a solar system?

Well, honey, the stability of planetary orbits in a solar system depends on a whole bunch of things like the masses of the planets, their distances from the star, and any gravitational influences from neighboring planets. Basically, it's like a celestial dance - if one planet starts acting up, it can throw the whole darn system out of whack. So, planets better watch their step if they wanna keep twirling around their stars nice and steady.