These manufacturers make sure that the hand painting is under the glaze and fired appropriately which protects the artistry preventing the need for special care.
Antique dinnerware with hand-painted patterns may be more fragile. They are more prone to crazing which is a deterioration process that includes cracking of the glaze.
To prevent crazing, it is wise to avoid drastic temperature changes. For instance, you wouldn't want to put a hot dish in cold water and vice versa. The changes in temperature can stress the glaze or even shatter the dish. Secondly, you should not use abrasive cleaning agents or cleaning pads.
Some hand painted dishes are not dishwasher proof, oven proof, or microwave safe. If you don't know that they are, don't use them that way. Hand wash the dishes in mild soap. Also, stacking fragile dishes can cause some problems so it is best to store them without the need for stacking.
My kids have made me some dishes over the years. Some of them have hand painting on top of the glaze. Decorative dinnerware pieces like these are solely for decorating, not for use as dinnerware.
With homemade dinnerware you need to be cautious about putting food or drink in it because of the possibility of lead exposure. Dishes that are appropriate to eat off of are made with lead-free paint and fired properly to be food safe. If you are unsure about lead content, you can test the dishes with a lead test kit to make sure that it is safe to eat of.