401k with traveling

Are there any healthcare workers that can offer me advice? I recently started traveling for work and contributed the max 401k for this past assignment. I’ve decided to go with a different company for my upcoming job. I will be contributing the maximum to their 401k as well. I plan to pick the highest-paid travel assignment, which means I may work with several companies. Should I roll over my 401k after each travel assignment or switching companies or after I am done traveling?