That is a question that I have struggled with myself over the last 3 years. To raise rent or not to raise rent.
Advantages to raising rent: Rent keeps up with inflation, expenses don't out pace CF.
Disadvantages to raising rent: higher turn over, increased turnover costs including remodeling to keep the from looking dated.
So if you took the amount shown above and divided it across 15 years you get a average of 18$ a month. which gives you a increase of 216$ a year. Over the last 15 years you would have realized a extra profit of 25920. Assuming that the tenant was ok with those increases then no problem. You just made a nice chunk of money.
No lets assume that because of your rent increase policies you realize a higher turnover rate. With one month vacancy & "freshening" costs. To keep the math easy, lets say it costs you on average 6k. As long as you expected less than 4 turnovers in 15 years then I would say have at. But if you expected more turnovers than that then I would say not to do it.
I personally have only raised rents upon turnover.
Someone should probably do a study to see which has made the most sense historically.