Clutch Replacement

I just had the gearbox from my '88 R 100 refreshed. Five new bearings, seals and circlip upgrade. It has 81,000 miles so while the transmission is out, it is a good time to replace the clutch.
The friction plate measures 5mm.
That said, when replacing the clutch, besides the friction plate and pressure plate, must the carrier plates also be replaced? If so, help me understand why.

Because single plate clutches wear in a very flat conical pattern. The parts that contact the friction plate should always be replaced as a set IF you expect to full service life out of the clutch assembly. I found this out the hard way.

Over time, the pressure plate and clutch carrier plate (two halves that contact the friction plate) wear in to develop a flat conical wear pattern that you can see by laying a metal straight edge across the contact face of the pressure plate. At the outer edge of the pressure plate the straight edge will of course lay in direct contact on the perimeter. The wear pattern will be evident as a slightly increasing gap below the straight edge as you near the center point of the pressure plate circle. Same for the clutch carrier.

If you just replace the friction plate, it will really only contact the metal plates at the outer radius. Then as the friction plate wears it actually decreases the contact area, which leads to eventual clutch slippage, which accelerates the wear pattern, which accelerates the slippage, which,....you get the idea.

I learned this the hard way trying to be a cheap-ass and only replace the friction plate on my 94 R1100RS. Only got 20,000 miles on that clutch job before the clutch strted slipping again.

Duly noted. All replacement parts have been ordered. Thanks,
Rick