The average yard is over-watered. Many plants, such a junipers, oleanders, trees and 90% of shrubs, can easily get by with being watered once a month or less.
Plants will show it when they need water. In most cases you will not harm a plant by allowing it to get to that condition.
The use of mulch around the plants keeps moisture in the soil and will also prevent the top inch or so of soil from drying out quicky. It is especially helpful for shallow-rooted plants.The rule of thumb for root depth is that the roots are as deep as the plants are tall, if watered correctly to begin with.
For most tall plants the use of aw ater rod that goes into the soil will help put the water where the roots are, and fan be used for feeding the plants, too. It saves on water and eliminates wasting surface water.