For pots and window boxes a long wand with a fine rose end keeps you from needing to stoop and delivers the water right where you want it. For any watering device attached to a hose buy a brass shut off valve that attaches to the hose end so you can easily shut off the flow of water between tasks. Soaker hoses made from recycled rubber are an inexpensive means to get the efficiencies of drip irrigation. They work well for shrub and perennial beds. Automatic watering systems on a timer can be water savers because they can be set to water only at night when the loss of water from evaporation can be minimized.
Overhead irrigation is appropriate for lawns and large shrub beds.
Watering Efficiently Any technology, no matter how simple or complex, is only as good as the user so the primary rule is to learn how to use any of these devices efficiently. Most gardeners over water by applying too little water, too frequently. Test your watering by digging into the soil after irrigation to see how well the water has penetrated. A few hours after irrigation the soil should be moist but not sodden to a depth of 12 in. A good rule would be to water deeply but infrequently.