Do you think travel stress increases with the number of trips per year?
Only half the time.
Stress can increase or decrease with frequency of travel. It normalizes over time. Infrequent travelers show a wild variability in the amount of stress they experience. Some experience a high level of stress while reshuffling home and work responsibilities whereas others who rarely travel may view the experience as a treat.
Regardless of where they start, most people's stress normalizes over time. The novelty wears off. Reshuffling gives way to routine.