TESB taking place over months makes some sense if you assume the Falcon has reserve foodstuffs to sustain the crew for long journeys. That way Luke has ample time to do his elementary Jedi Knight training with Yoda on Dagobah.
That would mean the captain and princess have been wearing the same clothes for months. Even if the clothing does get cleaned, wouldn’t Solo have changed into a different set of clothes instead of wearing the same outfit?