Receipts and records to keep

The rules

• You must prove expenses. "You can't deduct amounts that you approximate or estimate."
• Record expenses at or near the time. A weekly log counts as timely.
• Receipts are required for all lodging and for any other expense of $75 or more. Below $75, a log entry with the amount, date, place, and business purpose is enough (Pub 463 ch. 5).
• Keep records generally 3 years from filing; 6 years if income was underreported by more than 25%; 7 years for bad-debt or worthless-securities claims (Pub 583).

Travel contracts

• Home lease or mortgage statements, plus utilities during assignments
• Rent paid by bank transfer, not cash. If renting from family, a written lease at fair rent.
• Driver's license, voter registration, and vehicle registration at your tax-home address
• Visits-home evidence: fuel receipts, boarding passes
• Each contract and every extension (with the date agreed), plus the stipend breakdown
• W-2s (check box 12 code L and code TT), 1099s, and your own 1099 income ledger

1099 side work

• Separate bank account and card for the 1099 business
• Receipts or invoices: licenses, CEUs, certifications, insurance, software, equipment
• Phone/internet business-use calculation
• 1099-NEC/1099-K forms, plus your own income ledger
• Contemporaneous mileage log: date, start/end location, business purpose, miles
• Home office: a floor sketch, measurements, and photos showing exclusive use

Sources: Pub 463 (2025), ch. 5; Pub 583 (Rev. Dec 2024), Table 3