Frame / Springs: Front Spring - When to replace?

[wdsj]

59 Hawk - springs are original
how do you know when to replace springs? Should they be replace just because they are over 50 years old?
I plan to replace all the front bushing, springs also?

[StudeRich]

When the coils are touching each other, and or when the front end is considerably lower than the rear. There would be "bottoming out" on medium to deep dips, bumps etc.

The cars that used the evenly spaced coils (usually the H.D. Coils or pre-1956 [6 digit part #] ), always last a lot longer than the "Variable Rate" type that are close at the top and wide at the bottom.