I put a hairdryer on low into mine to warm them up a little bit, not much really at all, but enough to make them nice to put on... then I tied them up good and tight, and spent the day walking about the house in them. They definitely felt more comfortable than my last ones, and they broke in great, and noticed no fatigue or pain. I believe it was due to finding a boot that fit my foot well. Not to knock heat molding though. Back when I played hockey, I wore Vacuum Tack's which got heated, then they sealed your foot in a bag and used a vacuum to mold them to your foot. Worst experience ever, but having skates instantly broken in was well worth it.