Once the installed height has been established you can use a spring pressure tester to determine the state of the springs. Obviously, this method of monitoring spring life by comparing pressures ...

Check out the Erson Cams racing valvespring tech and some of their sound rules to follow. You'll find that valvesprings are more complicated than they seem.

“Coil bind” occurs when a spring’s coils stack solid at or before full camshaft lift. How Much Valvespring Coil-Bind Clearance Is Safe?