Modern experimental studies on SCO processes, whether they are induced by pressure or not, are usually accompanied by simulations. However, conducting such simulations in a meaningful and reliable way is far from trivial, owing to the intricate interplay between temperature and pressure in the SCO process. The T 1/2 temperature, i.e., the temperature at which the HS and the LS state are equally populated, is a key observable, which necessitates some statistical analysis. Moreover, it is remarkably difficult to find an accurate wave function based method or density functional that predicts the spin state ordering and the energetic difference between HS and LS states accurately. The performance of density functionals in the calculation of the energy difference between HS and LS states has been studied fairly early, and reparameterized density functionals with an optimized amount of Hartree-Fock exchange have emerged as successful tools to reproduce the correct electronic configurations. Despite these technical challenges, a number of computational studies have either successfully reproduced experimental measurements or delivered fundamental insights into the SCO process. The HCFF method, for example, has been used to study octahedral metal-ligand model complexes at the DFT level. It was found that the amount of pressure required to induce SCO in different complexes depends on the position of the ligands in the spectrochemical series. Based on these result, fundamental design guidelines for complexes with a tailored SCO pressure could be deduced.