I can wear them all day if I do not put my big toe (great toe, in medical terms)  in the big toe hole.  The right big toe is just a tad to narrow for my big toe, so it is a bit uncomfortable if I try to squeeze it in there for any length of time.  So I just ignore putting my toe through that webbing, and there is no mal-effect- I just crush the webbing down and I cannot even tell it is there.  But then, when I want the stability provided by having the great toes in their loop of webbing, I squeeze it in.