Holiday season, I feel this is the highest risk period for my trees as it is hot, the need for regular watering is critical and it is a time for holidays.
Unfortunately I do not have any people nearby that I can rely on to water them so I have a technical answer.
I have set up a system of overhead sprinklers and a computer controller that switches the water on and off at pre-determined times. This is a bit crude as you have to guess when the watering need will be and for how long.
I go for an early morning and an evening cycle of 3-5 minutes each. If the weather is cool, overcast and wet then they get a little too much water but it does not harm them for a week or two. If it is warm then they survive.
I switch this on a week before I go away so I can ensure that all trees are covered and no leaks or problems are there.