I have 2 dashchunds and I leave them both in the garden during the day. It seems to be the norm for this part of the world. I certainly wouldn't be too happy leaving them indoors during the day. They spend much of their time chasing lizards and other critters around the place. They have the carport for shade and plenty of water.
They probably only get taken to the beach for a walk once or twice a week
That's the thing if you've got a big garden and two or more of them then it shouldn't be an issue... they can run around and have the company of each other. Tis surely more of an issue if there is only one of them as they're not going to play, chase stuff etc.. by themselves.