Calculating debt to income?

[Benjamin Branson]

So I own two rental properties and cash flow about $600 a month between the two. Both are long distance. I am in the military and know that I will be moving to a new duty station next year. I am wanting to buy another long distance property (3rd property) but I also want to house hack when I get orders to move (4th home). My biggest concern is that when I move I won't be able to get a loan for a fourth house because my debt to income might get too high. Should I be concerned that I won't be able to get a 4th loan? How do I know when banks will no longer give my a loan because of my debt to income?