Does the car clunk or rattle over bumps? With 36K miles, most of those parts should still be good. Like Driller said, the rubber might be dry rotted though. Even if the lower ball joints have rotted rubber, as long as there has been grease in them, they are still good. I would take a look at them and see if they still look sealed. before just throwing parts at them. Same for the upper control arms, they are one of the first thing to clunk if they go bad at the bushings, and the ball joints don't often go on those before the bushings do (both upper and lower control arms come with the ball joints and bushings and are replaced when you replace the complete control arm). Same with the front stabilizer links, I would wait until those rattle/clunk, I've rarely replaced the rear links, usually a good tightening will do. If the air ride is still good, I would think a dessert garage has taken good care of all that rubber and I wouldn't jump at the opportunity to spend all that money. Maybe take it to a good local mechanic, have him look at it and ask him if he see's anything that needs immediate attention, then compare the 2 estimates?