[ZOA NOM]

If you're doing it correctly, there should not be increased wear on the clutch plate. What is important in the double-clutch is the engagement of the clutch while the transmission is in neutral (on the way to the lower gear) and you are revving to match the input and output shafts. With the clutch engaged, there should be no wear. If you are double-clutching without revving in neutral between the gears, then you are defeating the purpose, which is to match the speeds of the input and output shafts in the tranny, not match engine RPM to car speed. Practice will achieve a smooth, transition punctuated by a short throttle blip in the middle of the process.