Further, the simulation timescale itself is a key consideration. It is tempting to directly follow prescribed methodology, either from previously published studies or tutorials, and use it as precedent for determining an appropriate trajectory length. A key consideration here is the intrinsic dynamics of the system that are of interest. Some biomolecular processes are fast, and therefore may be easily observed multiple times in a single trajectory or over several replicates. Other dynamics are much slower and require extremely long simulations, many replicates, or biasing forces to observe. Investigators should carefully consider these aspects when planning the length of their simulations; there is no "default" selection for a simulation length, because this property is inherently linked to the dynamics in the system. In addition, it is critical to assess the convergence of the simulation; that is, analyzing quantities of interest to ensure that they are not systematically varying with time. If adequate convergence has not been achieved, the simulation outcomes lack robustness.