Irrigation is not well understood. Water is commonly applied too frequently and in small amounts, resulting in waste and less than optimum growth of the trees.

Fruit trees have a roots which are 3-4 feet deep from which they extract water and nutrients. Most of the water and nutrients are extracted from the upper 12-18 inches.
 Deep watering helps the plant’s health. I highly recommend watering deeply and infrequently. Southwest soil is high in salts and low in organic material. If you have a drip system, using a 1 or 2 gallon of emitter, let it run for few hours so that it soaks at least 3 feet into the soil
 The frequency of irrigation depends on the soil type. Sandy soils will need more frequent irrigation than clay soils. Water deeply so it penetrates soils at least 3 feet down. Remember to keep the trunk free from water to prevent diseases.
    Most soils in southern Arizona hold between 5 and 7 inches of water in the upper 3-4 feet .This is the moisture used by plants between each irrigation.
 Moisture storage in soil is depleted by evaporation from the soil surface and plant use. Evaporation and plant use of moisture is effected by the weather. In warm weather, plants need more water to compensate for growth and transpiration.
 I have both a bubbler and a drip system .The bubbler heads are close to plant, and I let them run for 2-3 hours every 7- 14 days in summer months. Because all 70 bubbler heads are connected from one line, the flow of water is slow and it soaks a  3-4 feet diameter area around the plant.
 As tree are growing, the drip line is moving further away from the trunk. I use 4-6 one gallon drip
emitters around a canopy and let them run for 3-4 hours every 7-14 days in summer
 Mulch aids in preserving soil moisture, resulting in less frequent need for irrigation.

I recommend watering deeply every 4-6 weeks during winter months.