There have been many studies (most by strut/shock companies, but a few by the transportation safety board and insurance institute for highway safety) that have tested shocks and struts of all types and found even the best of struts/shocks have a "quality lifespan" of a max of about 60,000 miles even though many are not noticed as being worn until around 100,000 miles. Braking, cornering, noise reduction, and bump management are all greatly improved when changing shocks/struts at about 60k miles. It is quiet noticable even when using the exact same model strut/shock unit (which is recommended to use stock LS struts and not some crap Monroe stuff as the LS has allot of design work in the originals and work best when you have a stock ride height).
Me, I let my shocks/struts go too long in most cases on most vehicles. I might try sway bar end link bushings and inspect the sway bar bushings for possible replacement before doing struts just cause struts aren't cheap and I like to get all the use out of them I can. Either way, I'd not put new struts on without being 100% sure the sway bar and end links all have good bushings.
