In contrast to DFT, the accuracy of wavefunction-based methods can systematically be improved. While MP2 is often comparable to (hybrid) DFT approaches in accuracy, CCSD(T) is much more accurate for energies. If large basis sets (at least triple-zeta quality) are used, they often approach "chemical accuracy" (i.e., <4 kJ•mol -1 error). There are two ways to determine the accuracy of a computational method: (i) comparison to a theoretical benchmark method (e.g., CCSD(T)) or (ii) comparison to experimental data. Usually, the first approach is done in molecular chemistry since benchmark data are available. In surface chemistry, and thus also AS-ALD, the lack of available benchmark methods leads to the second approach being more favorable. Unfortunately, not many accurate experimental data are available in AS-ALD which would allow to quantify the errors in structures and energies made by the (DFT) modeling. Assessing the accuracy of other methods (kMC, AIMD, etc.) has the same drawback of lack of benchmarking data. Some exceptions exist: Recent thermodynamic measurements for ZrO2 showed semi-quantitative agreement for the DFT approaches it compared to. It was shown that the surface model in the theoretical description is important for this comparison and that inclusion of dispersion interaction treating methods might change the results qualitatively. These kinds of measurements are crucial for further establishing the accuracy of DFT and other modeling approaches for ALD and AS-ALD.