Using a manual spreadsheet to track your mileage has several drawbacks, such as the need to manually enter data that can be prone to errors, omissions, and inconsistencies. It also does not account for traffic, detours, or route changes that could affect your actual mileage and reimbursement, nor does it provide any proof or verification of your trips. Additionally, it does not allow you to easily attach receipts, photos, or other supporting documents to your expense reports and does not integrate with your accounting, payroll, or tax software. In contrast, a mileage expense app offers many advantages. It uses GPS technology to automatically track your mileage and route accurately and consistently, adjusts your mileage and reimbursement based on the current IRS rate or company policy, and provides a map, log, and summary of your trips for proof and verification of your expenses. Furthermore, you can add receipts, photos, notes and other information to your expense reports which are stored securely in the cloud. Lastly, it integrates with accounting, payroll or tax software and allows you to export expense reports in various formats.