Our pots are handmade, using stoneware and porcelain clays, and high fired. That said, their ability to withstand hard usage cannot compare to industrially made dishes, so you need to care for them accordingly.
They are fine in the dishwasher and microwave. Pots can be used in the oven if so indicated. As with all handmade pottery, you want to avoid extreme temperature changes. Avoid pouring boiling water immediately into your cup. Let the water cool just a bit, and preheat your cup with warm tap water before proceeding.
Stoneware baking dishes are fine to go from room temperature to a hot oven. You might want to avoid using frozen fruit to make pies or crisps. Do not take baking dishes from the fridge and put them into a hot oven.