Quasi-static numerical methods are much wider used for simulating MEMS devices as compared to full-dynamic analysis. Quasi-static models are uncomplicated to set up and have shorter simulation times. Furthermore, it is assumed that the inertia of moving masses can be neglected in MEMS devices because of their tininess. This paper investigates whether kinetic energies plays an important role in elastomechanics/electrostatics coupled-domain analysis since especially electrostatic actuators are characterized by very large actuation and thus acceleration forces. It is found that for certain actuator configurations, the dynamic behavior affects even apparently static parameters such as the pull-in threshold voltage of electrostatic actuators, especially when considering their high degree of nonlinearity. The paper identifies the most relevant device parameters and investigates their influence on the accuracy of the simulation results of quasi-static methods as compared to full-dynamic analysis. Based on these findings, the paper provides with practical guidelines on the choice of the appropriate simulation method depending on the device configuration. Moreover, the paper provides an error estimation of the simulation results obtained by quasi-static methods, using full-dynamic analysis as the reference.