Push on the front of your car, unless you have access to a lift or something and grab hold of the sway bar, and bounce the front up and down. Bounce the front end up and down a couple times and let go. If the front end keeps moving up and down when you release then it's bad strut(s). If it pretty much stops bouncing right after you let go then your struts should be alright. The struts should stop the front end from bouncing pretty much right away. You should be able to tell when driving, too. Take notice of the front end. Go over some bumps in the road, like railroad tracks or a bumpy street or something, where you can get the front end to bounce around. I know there's technical names for that like "jounce" and stuff, but I like plain english myself.
------------------
1996 Mustang GTS
K&N, removed air silencer, 3.55s, turndowns after H-pipe (no mufflers)