Limitations
Risk analysis of dynamic systems: Markovian approach

For a process to be Markovian, all random events must be governed by exponential laws.

While this is quite appropriate for failures, it is more questionable for phenomena with near-constant durations, such as system reconfigurations after a failure, the transport of maintenance teams to the site of their intervention, the supply of spare parts, or the alternation of day and night, which may need to be taken into account in the models.

This criticism...