@Leigh Ann Smith
The 50% rule is a good rule of thumb for keeping you out of trouble. It wasn't so much designed for the expected expenses, property taxes, insurance, etc but for the bigger unexpected ones. Those are the ones that are going to ding you when you least want it.
Hold the property long enough and you're going to face capital projects. Roof needs replaced, furnace dies, repave cracked parking lot, your mother in law moves in with you. Well, you get the idea.
You can always consider reducing your debt service side by A) putting more cash down on the purchase or B) getting an equity partner(s) and splitting the pie.
I Have a mentor that liked to partner on investments. They said if turned out bad, at least you had somebody's shoulder to cry on. If it turns out good, you may accomplish more then you could have down on your own in the long run.
In closing though, the 50% rule is just a rule of thumb. And rules like thumbs, can be broken.
The ultimate test to me is, how well are you sleeping? Like Rip Van Wrinkle? A bear that gets up here and there during winter? Or, I can't sleep at all, I'm too worried! I prefer to sleep well at night. But you have to decide how much risk you're willing to assume.