Clutch Issue

I have a 1989 Toyotoa Tercel. I am the 2nd owner. 1st owner bought new and kept it 21 years and kept perfect records (even gave me all receipts). He fixed all problems and did all mechanic suggestions over the years. I am having a issue and it is new to the car.
It is the clutch. Doesnt matter if it is after a 5 minute drive or 5 hours. I can have a complete full clutch like it just came off the showroom floor. A while later, I can barely have none at all. It goes on cycles. It could last a few minutes or a few days.
I dont want to replace clutch, plate, bearings, cable, etc if it could be a more isolated problem. Please help.