When artifact equilibration times run in weeks and months, it may be more important for the museum to examine and worry about longer RH cycles instead of minute changes. This is not to say that small RH fluctuations should not be considered. Small RH fluctuations can lead to fatigue in materials. Usually small fluctuations are not important when doing a risk assessment and cost-benefit curve. But for some materials, each cycle causes tiny fractures to grow.
Deterioration increases as cracks are opened further.
Research on painting deterioration by Stefan Michalski suggests that this may be a cause of surface cracks. The amount of mechanical damage is directly related to the type of material, the constraint on the material and amount of RH change. Small changes cause small effects. Big changes cause big effects. If tension climbs in a constrained material it eventually reaches a breaking point.