A toilet can leak, have you tried a dye tablet?

Should you worry; I would worry if the old pipes should be replaced. how long do you plan to live in the house? Do you have the resources to remove and replace. Is this a good time to remodel?

If nothing was running, the meter wouldn't have moved. I agree with Jim, likely a small toilet leak, or small faucet drip.

Thank you. I will check the toilets. And then the line to the house.

It's a good idea to figure this out, especially in case it gets worse. However, where I live, water is less than a penny a gallon, so, if your calculations are correct, that would mean paying less than a dollar a year for what is being wasted. Your loss is so trivial - a quart a day - that it could be coming from a single hose bib or faucet that is slowly going drip-drip-drip. If it were a toilet with a leaky flapper valve, I would expect to see a much greater loss. As it is, your loss is equivalent to flushing a water-saving toilet once or twice more a month, or an old-fashioned, higher-use toilet one extra time about every three months.