I completely agree with what Bob S. said as I have seen this play out as a mechanic over the years with customers, friends, as well as my own cars. sometimes because the new springs are just so far off and sometimes because they just didn't meet a particular persons expectations. If you like the look of the ride height now that is half the battle but unfortunately coils can sag enough over the years to cause ride and handling problems. This is usually directly related with original springs to miles and how well the car was maintained back in it's daily driver days. after years spent working under a lift the biggest culprit being old spent shocks. All you have to do is cut an old shock apart and see the piss that comes out that used to be oil to understand that it's not just leaking seals that condemn shocks. The shocks job is not only ride comfort but to limit spring jounce and body roll. Weak shocks left on our old used cars back in the day accelerated spring wear tremendously. All that said you need to look under the car while on the ground or a 4 post lift and look to see if your lower control arms and bottoming bumpers are roughly in the right positions. The lower control arm should sit either level from frame connection to ball joint or slightly lower at the ball joint end. also look at the space between the bottoming bumper and it's stop and there should be a decent gap. if everything looks decent but the bottoming bumper looks pretty pounded up you need shocks. Also if the ball joint end of the arm sits higher than the frame end you need springs. Of course if you want to be fussy you could measure ride height but with the above method there is no need to.