My IRs were uncomfortable until just recently. They took about a year to break in. They felt too tight across the ball of my feet, the heels would slip, and the soles just felt like a plank of wood that didn't conform to my foot at all. They're comfortable as can be now.
Seems like a long time but I would agree. My muleskinners are a little over a year old and I would saw they are just about perfect. I picked up a brown pair a month or so back and they have a long way to go.