I finally got up the gumption to do a basic preparedness task: Put a wrench near the gas meter, so that if I need to shut off the gas supply I don’t need to search for the tool.
It’s fortunate that I tested the wrench by trying to turn the valve (just a little; never shut off your gas if you don’t have a leak). I couldn’t move the valve even a little, and I thought it must be rusted in place. I was honestly alarmed: I could have been stuck with a gas leak in the house and no way to turn off the gas supply!
I ended up calling Puget Sound Energy. They quickly sent a very nice lady who told me that the valve is just hard to turn, and my wrench was simply too small. You need a lot of “wrist power” to turn the valve, she said, and you need the lever of a long wrench. (She also pointed out her “12” earrings and wished me a genial “Go Hawks!”)
This is a great argument for practicing your procedures! I would never have known until it was too late. I went to True Value and bought a 12-inch wrench for $17. I tested it and it works. It’s now resting in a plastic bag next to my meter, and I feel better!
The nice lady told me you can sometimes find large wrenches cheap at second-hand stores. She also told me that PSE will diagnose problems with any of your gas appliances for free. If repairs are needed, they will write an estimate that you can compare with private companies.