Well, my experience of one confirms this belief. While I was under the car (240D) preparing to bleed the clutch master cylinder I wondered about this. I wished then that I had ordered the slave at the same time. I'm going to be back there again soon. What would you do if the slave cylinder has already been replaced (130,000) and the master needs replacement at 142,000? This is the situation I'm facing with my 190D. I hate to replace parts unless necessary (read cheap). Am I tempting fate once again?

Kevin
1979 240D manual
1984 190D manual