You want to make sure the arch of the shoe is centered properly under the arch of the foot. Next, you want to make sure that the heel is fully supported on the footbed. Then you will have the correct fit.
Note: All OOFOS styles shown on this website are in US sizes.
Keeping your OOFOS looking good as new is easy. You can either toss them in the washing machine with a mild detergent or scrub them in the sink with a brush and mild soap. Once washed, towel them dry and they are ready to wear immediately - or put them out to dry in the shade.
Take care of your OOFOS when you are not wearing them: As your OOFOS are made of that extra comfortable, soft proprietary foam - it's best not to store them under a pile of shoes. This may lead to crushing and creasing - which won't hurt their effectiveness, but this will eventually make them look less than perfect.