I bought these for a trip with my daughter.  I put them on and wore them continuously for 3 weeks.  No problems.  No breaking in.  They were wonderful support for walking - and I walked everywhere!  I have plantar fasciitis and have been wearing sandals only occasionally with my orthotics velcroed to them.  No longer!!!  I now have 2 pair of Orthaheel sandals - this pair and a pair of flip-flops, which I have not worn for years but now can again.  Cannot recommend them enough.