I've always heard this, but when I drove a manual I always downshifted frequently and kept that car for 150,000 miles. I did have a clutch replacement somewher

I've always heard this, but when I drove a manual I always downshifted frequently and kept that car for 150,000 miles. I did have a clutch replacement somewhere in the middle, but blame that on starting on San Francisco hills more than downshifting.