I don't know how to tell if/when springs need replacing (or if they ever really do).

I just replaced my shocks and struts (they were pretty bad) and noticed how easy the rear springs are to replace (don't know how much they cost, tho). Front springs looked harder, but doable... (I'm not really interested in lowering the car much, just a smooth ride)

How should I decide whether to replace the springs?

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Joel Geerling
Red 91 Formula, 305 TBI
Edelbrock 14x3 open element
TBI 1/2" spacer
Hypertech street chip
Crank/Alt Pulleys
*
Exhaust is next!

 

if your car ever bottoms out, or if the tires ever scrape anything you need new springs. The front ones are changable, but you have to be very, very careful. You have to break the ball joint loose from the spindle, and using a floor jack, very, very slowly let the lower control arm down. when it gets all teh way down you will have to sort of pull the spring out, it shouldn't have much spring left, it shouldn't spring out after the LCA is all the way down. I did this when I did the front suspension, but didn't put in new springs, mine seemed fine

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'86 IROC 5-speed
305 LG4
edelbrock performer rpm intake
edelbrock 600 cfm carb
msd pro billet hei distributer
'95 3.23 rearend
hotchkis rear suspension
PST front polygraphite suspension
"speed kills. buy a f@&d, live forever."

 

The spring rate (stiffness) does not change over time.
The springs will settle with age though, meaning the car will lower itself some over time.
You won't need to change them unless you want to change the ride height.
If you want to improve the ride quality and have already changed struts and shocks try all new bushings too.