No break-in period at all, which surprised me for a trail shoe. The lacing pulls snug in one go and stays put on rocky descents, and the fit feels locked in without pinching.
Wore these straight out of the box on a wet, rocky trail and had zero blisters, which almost never happens for me. The snug fit and simple lacing keep my foot locked in on descents. Only gripe is they run a touch warm on longer summer runs.