Depends on what you want to consider a number. There are members who travel for business every quarter, Few just 1 or 2 a year for vacation.Question is how much is much and how little is little. Is 1 much or little? How about 10? 15? No one knows. Factors are factors it may be that one served in the military while others happened to get into North Korea out of curiosity. These are all guesses. So let's speculate less and just wait and see
So if you are asking me how much is much, then I would say every quarter.
Also, to your point around Military service. in my note above, I did mention, it is only "one of the factors, based on my conversation with friends who are in the same boat."
There can be lots of IFs and BUTs. Anyways, all the best.