Tricky Question: Average Suspension Life-Span

[Bayerische E53]

Hi All,

I know there's no cut-and-dry answer to this question but I'm going to ask it anyways: What is a ball-park estimate of the amount of miles an X5's suspension can take before it's in need of replacing?

My X5 has 150,000 miles on the clock, of which 75-80% are highway miles; most of the remainder took place on decently paved city roads. Also, the truck went about 10,000 miles towing a 5,000lbs load.

It's difficult to tell whether the suspension is getting soft/bouncy because I've driven the car since it had 85,000 miles and, as you all know, it's often times quite difficult to realize when something gradually wears out.

I'd appreciate any input. Thanks a lot, folks.