In the early days, populations of eggs and protonymphs are high and perhaps you haven't learned to control humidity in different weather conditions, washing 2x a week will be effective imho.
But if you can maintain low humidity for a longer periods, the dust mite populations in your home will go down and frequent washing will be less important.
But if you can maintain low humidity for a longer periods, the dust mite populations in your home will go down and frequent washing will be less important.