What are the conditions for removing training wheels? I have children who I'm trying to get stoked about riding bikes. I am prone to letting them try and fail, and learn from mistakes, gaining confidence as they go, but this doesn't work perfectly with their personalities. I was wondering if there was some community consensus on what what conditions should be met for removing training wheels. 


What should I look for in the rider? 
Are there any activities that we could do to build confidence?
Should I remove both training wheels at once, or one at a time?


I am looking for consensus, not necessarily the "right" answer, but a widely-accepted one.
Consensus seems to be more and more this:


  Do not use training wheels.


The most important part of cycling is not the pedaling, but balancing and steering. Steering is mostly done by leaning (therefore balance) and not by turning the handle bar.
Training wheels do not help in learning to balance the bike and actively prevent leaning.

Therefore it might be better to start with a balance bike (no training wheels, no pedals) to learn the essentials and add the easy part of pedaling afterwards.