Fully flexible temporal resolutions have shown to be a useful tool for improving the tradeoff between the runtime and accuracy of generation expansion planning models. However, no research has been done into the effects of considering short-term operational dynamics of thermal generators in models with such resolutions. Therefore, this paper complements the existing literature by adding start-up and shut-down costs to a large-scale energy system optimisation model with a fully flexible temporal resolution. The results suggest that the addition of start-up and shut-down costs significantly increases the runtime of the model, while providing a small increase in accuracy. Additionally, they show that a compact set of start-up and shut-down constraints outperforms a full set of constraints in terms of model runtime, while having the same accuracy.