Is it wasteful to replace bushings just out of principle?

[Honus]

I just got a 1985 300D with 174,000 miles. The car is nice and straight. It will go 80 without any vibration. My main complaints are that the front end tends to pop or clunk at low speed and the rear end sags a little bit. I often feel a clunk in my left foot, leading me to suspect that something is wrong with the strut rod (if that is the right name).

I am considering replacing all of the bushings and ball joints throughout the car. My thinking is that I intend to keep this car for a long time and would enjoy having it nice and tight. If that means new bushings every 18 years, then why not?

Am I wasting my time and/or money?