Replacement of the struts should be based primarily on how long they have been on the car. Even if the car passed the "bounce" test, the shocks may still be blown. My car would bounce for about one second when I tested the shocks and struts. There wasn't even oil residue. Despite this, all four shock absorbers were blown out along with the mounts and the strut bearings.
If you do the job yourself, it will cost about $450 for the shocks, mounts, struts, and the various nuts and bolts that get replaced as well. It took me about six hours total. Also, don't use OEM struts. They are too expensive and too soft.