I guess theoretically a Lagrange point is a single point in space, but in practice, how large are they? Assuming a station with the mass of the ISS, how far fro

I guess theoretically a Lagrange point is a single point in space, but in practice, how large are they? Assuming a station with the mass of the ISS, how far from the ideal Lagrange point can you be while still maintaining a reasonably stable orbit?