The 525i might very well be the most durable car BMW ever built. If given routine maintenance, it will run forever.
The E34s are prone to some rust, most often along the inside door bottoms.
This car has just 152,000 miles on it. Keep it maintained and you'll easily get another 75,000 - 100,000 out of it with minimal problems.
Located in Montclair, NJ, click here to see the eBay listing.