Based on our extensive benchmarking of 284 model chemistries detailed in Results and Discussion, we offer practical guidelines for selecting the most suitable method to compute ∆H • f for small organic molecules. These guidelines weigh three factors: (1) accuracy requirements, (2) computational resources, and (3) the chemical nature of the target molecules (e.g., charge and spin state). Unless noted otherwise, mean absolute errors (MAEs) refer to training set results with Petersson-type BACs. Computational cost estimates are reported in logarithmic seconds (log s) for each QM method, reflecting the approximate central processing unit (CPU) run time required for all QM jobs measured under our specific hardware and software environment, as applied to the small molecules in our training set.