Do you clutchless upshift?

So when I ride, after I get moving, I don't use my clutch. Just release throttle, upshift, and go as normal. However, a friend of mine swears it's "not good" even though I've been doing it for nearly a decade now and haven't had any problems. In fact, I personally think it saves the clutch wear if done correctly.

Do you do this? Or do you clutch upshift all the time?