A tehnical problem i found is quite common among BMW 5 series owners, is the excessive inside rear tire wear. This occurs mainly for cars fitted with large REAR tires like 275 to 285, and my car was the case too. As you can see in the attached photo, my rear tires face a sever wear on the inside.
The inside wear can be caused by multiple things, and a very possible cause can be the wheel geometry alignment. But after some research, it seems that after 50-100K km (range of the car, not tires) depending of the quality of the road where you drove your BMW 5 series, a small part should be changed prevently in the REAR SUSPENSION.
It is a BALL joint (bmw code 33 32 6 767 748) and it is the part with number 2 in the below rear suspension scheme. So i replaced these 2 ball joints (left and right) and had the wheel alignment again. This seems to have solved the inside wear of the rear tires.