||A theoretical study of a chemical system is focused on representing the system properly with a model and using it to accurately represent and predict physical and dynamical properties of interest. The trade off between accuracy of simulations using a theoretical model and its computational expense is an important consideration in choosing and implementing the model and accompanying force field. My research has sampled the two extremes of this balance. In developing the mW-Ion and mW/3SPNDNA models, a coarse-grained technique was used to simplify the interactions and significantly increase the efficiency of the calculations with respect to atomistic simulations. These models have limited transferability to other studies due to their coarseness, but reproduce properties such as solvation structure and ion dynamics quite well, and this with the ability to extend the simulation studies to timescales intractable for their atomistic counterparts. In later work, while investigating potential improvements to solid polymer electrolytes used in lithium battery technologies, an atomistic model with a polarizable force field was used in order to correctly capture the mobility of lithium cations. This involved a considerably larger computational expense, but was necessary to retain fidelity to experimental data. The advantages and disadvantages of the two sides of this balance is explored here, with detailed examination of the models and force fields used, their applicability, and broader impact in the simulation and scientific community.