One thing this discussion hinges upon is what are you defining failure as?
Concentric Failure slightly cheat form
Complete Concentric Failure
Obviously, complete concentric failure is not advisable to do every set. But I would hesitate to get close to technique breakdown on every set either.
As Ecko31 posted, stearing clear of failure in early sets, allows you to get in more total volume and allows you to get in more reps on the heavier sets.
James 1:16-17 ESV
Do not be deceived, my beloved brothers. Every good gift and every perfect gift is from above, coming down from the Father of lights
With God's help...Mens sana in corpore sano