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When the IRS says you must be away from home to deduct business-related travel expenses, they are referring to your so-called tax home. This may or may not be where you maintain your permanent residence.
Your tax home is your regular (fixed) place of business, employment, or post of duty, including the entire city or general area of your regular (fixed) place of business.
For travel expense purposes the IRS says:
Your residence may not be your tax home.
For example:
Your tax home is San Diego because it is your regular place of business.
This means your costs for traveling between Phoenix and San Diego, lodging, and meals while there, are not deductible because they are considered personal expenses.
Your main business location is generally where you spend most of your time and earn most of your income and is generally considered your tax home. To determine your main business location, compare the time and income associated with each business location where you work.
Phoenix is your tax home because it is your main place of business. Consequently, when you're in San Diego you're away from home. This means your round-trip travel costs between Phoenix and San Diego and lodging in San Diego are fully (100%) deductible.
If you have no permanent residence and move from city to city to work, your tax home is wherever you're working at the time; you're considered an itinerant. This would apply to someone who travels around in a motor home or trailer for example, and lives in it while in the work area. You can never be considered away from home since you have no permanent location to be away from.
To be away from home you must be away from the general area of your tax home substantially longer than a regular day's work and require sufficient time off to get necessary sleep before returning home.
Taking a one-hour nap in the car is not sufficient time off. You don't necessarily have to be away from home 24 hours, you just have to have enough time off to get necessary rest to function properly.
This rule, which requires that you get sufficient time off to get rested before returning home, prevents you from being able to deduct the cost of your meals on one-day business trips.
You meet the away from home test. Your transportation and lodging expenses are 100% deductible. Meal costs are 100% deductible for 2021 and 2022 provided the meal is served at a restaurant, otherwise the cost of the meal must be reduced 50%. The purpose of the temporary change to a 100% deduction was to help stimulate the restaurant industry.
You do not meet the rest test since there was not sufficient time to get the proper rest. You are not considered away from home. Your trip is a one-day business trip which means your meal expenses are not deductible.