As for plants - we grow gravel and weeds. My cactus died last summer from the heat and lack of water. Seriously. LOL
If you are talking about a rental, we just disconnect the electricity when we have a vacant apartment. We clean and leave the refer doors open.
We also dump bleach down the toilets and plumbing lines, otherwise roaches will come up out of the sewers. If you are leaving it for more than 2-3 weeks the water will evaporate from the traps leaving a route from the sewer. You can also put painters tape over the sink and tub drains and stuff a bug killer soaked rag tightly into the toilet (after flushing an draining it) to keep the nasties from leaving their sewer.
Be careful if you leave toilets for long periods without flushing as the wax seal can dry out and crack.
Remember to shut off the stop valves and hot water valve, and or the main service valve. We have irrigation now for the cactus that I'm trying not to kill this year... so we leave the main on, but shut off fixtures.
We also flip the breakers on the stove, water heater, etc. And unplug electronics. Our electric runs about $13.00 a month for security lighting.
If we are talking your own home and you have heat sensitive art or materials I would suggest leaving the AC to about 85, 90 is getting kind of warm. A lot depends on your insulation. Our house is extremely well insulated and never seems to go over 95 even when it's 115 outside.
We have only had our house here for 3 years, but last year we closed it up from the end of May until mid October. We left the AC off and forgot to unplug the refrigerator, so it was on for 4 1/2 months - with a forgotten piece of watermelon inside... "that" was a creature nightmares are made of... LOL)
If we are going back and forth between homes due to vacancies or whatever, we have a great neighbor who has a key so we just call him the day before we arrive, and he turns on the AC to about 75 so everything is cooled down by the time we get there.
We don't display any oil paintings at our house in AZ. It's just too dry, or else it's too hot and humid. We display various sculptures, framed prints and photographs, and metal wall art. We keep our antiques and nice furniture at our house in CA where the weather is more moderate.
You might look into a maid service that could come by once a month and dust and flush the toilets, etc.
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