I've always downshifted, throttle blip happens out of racing habits.
I've had a 2010 Mazda 3 for 5 years now, just did a brake job last summer, after 140,000 kms.
2002 Subaru WRX, bought used at 225,000 kms, changed the clutch (original), as it was slipping when I bought it.
Clutch material is designed for wear, much like brakes. It will wear, it will need to be changed after time. It all depends on your driving style. Increased performance/High HP needs a stronger clutch to hold.
All that being said, if you downshift properly, you won't wear your clutch more then normal, I always say keep it in gear for safety.
All the other drivers are out there to kill you.