Not exactly sure how much water it's saved, but we're only watering what needs it and not walking paths and such. Well, mostly.
We have drip irrigation. Mostly to make life easier on us. Watering 1200sf by hand is, well, long and tedious. With it set up on a timer, it can water early in the morning before the sun comes over the neighborhood trees, and in the evening after the sun disappears behind other neighborhood trees. And I don't spaz out and forget to water things for a week at a time. Which yes, is bad for my plants.

And minimizing overhead watering is a good thing, at least for us with my crazy assortment of so many different things.
Getting all the parts we needed/wanted has taken time and money as hubby's had to scour various local places for certain things and even had to get something off Amazon this week, but we should be good to go for another 5 years or so with what we've got. We did try soaker hoses one year, and that was a flop. With two boys that don't listen well about staying out of the garden (i.e. sharp little shoes and trucks), our incredibly hard, mineral-laden water, and me also accidentally stepping on them, they barely lasted one year. A ton of mineral build up was in 'em as well when we finally yanked them up.