Well I agree to a point on what needs to be change. From my own experience, I changed the timing belt and tensioner at 100K on my 91 940SE. I choose not to change the seals as there was no evidence of leaking. As to the possibility of leaking before 150K, yes it could happen. On my 82 245 I never changed the front seal or seal on the intermediate shaft and the car had 180K when the engine had a bearing problem. Water pumps must depend on the model, as the 82 I changed the water pump approximately every 50K, about the same as on my 75 164.

I left the water pump alone as every thing looks fine and no leaks anywhere. I am more concerned with the plastic valve on the heater hose, then the water pump.

There is no evidence of leaking on the seals which now have 115K. Since I bought the tool to lock the crank pulley in place, changing the seal is a relatively easy task.