Usually, the first sign of a clutch failing is slipping at freeway speeds in fifth gear, progressively working backwards through the gears. A high clutch engagement on the pedal before the vehicle starts to move is also a sign of clutch wear. Sometimes this can be adjusted (at no charge) and many more miles driven.
Proper clutch replacement would definitely include resurfacing the flywheel to true flat on a grinder not a lathe, replacing the release bearing, pilot bearing, clutch disc, and pressure plate. Additional items to consider while the transmission is out are seals.
The replacement of the engine rear main oil is relatively easy on most vehicles with the clutch already removed. It's probably leaking anyway and if it is not, with the amount of miles on it, likely it soon will. We remove the seal and polish the carbon deposits off the sealing surface and install the new seal.
Axle seals and drive shaft seals should also be considered. They have lost their elasticity from the years of use and, in the process of transmission removal, they've just been disturbed. It's the same installation procedure as the rear main seal. Lastly, if the transmission does not have a drain plug, we'll set it upside down to drain the fluid before installing it.