After whitening, avoiding foods and drinks that stain teeth, such as coffee, tea, red wine, and dark sauces, is crucial. Clients should be advised to steer clear of these items for at least 48 hours post-treatment to protect their results. This is particularly important immediately after whitening when the teeth are more porous and susceptible to stains. Providing this guidance helps clients maintain their bright smile and ensures long-term satisfaction with their whitening treatment.