poweramp tube matching

In a push-pull circuit (I'm guessing 85% of tube amps) if the pairs of push-pull tubes DON'T match, the weaker tube generally causes the stronger tube to wear faster, is what I've read.
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Newbee, I recently read an article on the very point you raised, namely

"when each tube can be individually biased doesn't that overcome the problem you bring up?"

And the author explained why it doesn't compensate for the tube's not matching. I'll try and remember where I saw it ;--)