With our less than average rainfall and subsequent drought year with added water restrictions, it makes sense to look at your irrigation system. If it is an older style with spray heads, that is less efficient that the drip type systems (there have been many improvements in these systems). A spray type system loses much water to evaporation and more under windy conditions. (water blows off the intended area)
As budget costs are always a factor, you can improve an existing system by simply giving it a close scrutiny and fixing problems. Another way to save water with an existing system is to change the technique of watering.
First, testing the system is fundamentally important. A manual turning on and watching where the water goes is very important. You will easily detect breaks, clogs, etc. as well as note missed areas, over watered areas.
Now for the second tip, you can change your watering technique by double watering. This is easy, it involves turning on the system to water once, wait for that moisture to soak in, then water again. What you area accomplishing is getting water to a deeper soil level and this in turn will help stimulate deeper root growth. This allows your plants to go longer between watering intervals as they have a deeper moisture reserve to tap into. It is also very important to let the area dry out between these deeper waterings. This allows air to return to the soil structure so roots can breathe. If you do not do this, you will drown your roots and they will die. This simple technique will save water over time.
Incidentally, the technique works equally well for containers!
If there is a heat wave and it occurs on a non-watering day, all you need to do is to wet the ground area and that will provide moisture and cool the plants down. Try not to get water on the leaves if in full hot sun, as it can cause sunburn. Of course, if the plant is wilting and needs to be watered, water it!
Drip irrigation is most affective to get water directly to the root zone with minimal evaporation loss. Microspray heads water an entire soil area whereas individual emitters may not and you may have to install more of them. What you are trying to accomplish is wetting of the root zone area thoroughly.
A quality, EASY to use timer/controller is very important. You should find it easy to use so you can change the program to anything you wish. Spending a bit more on this is money well spent as a hard to use controller is difficult to figure out and it takes much of your time.