Troponin

There shouldn't be much more wear and tear on the clutch from double clutching or rev matching. However, double clutching isn't necessary on modern street cars because they all have synchronizers. Rev matching to slow down doesn't really effect your clutch life much either if you match it correctly.

tbear853

True, "double clutching" (ie: "rev matching" .... same-same in my use) isn't needed on most upshifts or downshifts these days (probably not since the forties unless an old truck, so near never in "my days" ), but doing it when you have the luxury of time (and except in a drag race, when do you not have the time to anticipate and make smooth gear changes considering the car is still moving the whole time?) ... just eases the burden on the synchronizer rings and the friction surfaces that are tasked with slowing or speeding up gear trains for that next gear (and besides, you will get more consistent smooth shifts that are less likely to shock the rear tires or suspension at in opportune times) depending on which way you want to go.

It doesn't take the place of synchronizers as they still do the final match up before engagement of the next gear, you've just lessened their job some. I've done it both ways over the years, a "mix" so to speak. I've also driven vehicles with bad and broken / cracked synchro rings I had to wait to fix (result from when I was also power shifting as a young toad, sometimes a ring broke or cracked) and then I made good use of the technique.

Besides, I know that Bullitt's Ford Toploader was synchronized ....