Question: How often should I water my apple tree?
Option 0: If the tree is one or two years old, give it a really deep watering twice a week, or less often if the rain is plentiful in your area. After a fruit tree is 3 + years old water only when the soil is dry to 8 inches or so. When the tree is just establishing itself, deep watering promotes deep roots and shallow watering promotes shallow roots, a liability for a tree.
Option 1: Apple trees don't need to be watered at all unless you live in a complete desert. Let mother nature take care of it.
Answer: 0