Would this be wise to use when we are in a drought ? What is a reasonable about of time this can be on ?

Each nozzles uses about half a gallon per hour so that’s about 3 gallons per hour for this kit. Running this while you are sitting on the patio is not a major water consumer. Rich people in Los Angeles spend thousand of dollars each month to keep their estates green. These tiny kits have little to no impact in comparison. Use it wisely and turn it off when you are not in proximity. I feel zero guilt. Much better than consuming a bunch of electricity with you AC.

That depends on your discretion. If you think it's going to be wasting too much water then don't use it. Mine has six emitters and emit a very very fine spray of water, so I'd not expect a single nozzle to shed more than a gallon per hour. Six gallons if you have a six emitter system. I have two of them, so 12 gallons per hour and that's not much.