No one can tell what the feature holds when it comes to the revenue stream of a rental property. When you are researching market areas you want to make sure that the current market area of the investment property you are interested in is producing the type of income you want your investment property to generate. Once you identify the rental amount you want to receive, this price along with the amount you are willing or able to pay for your investment property will greatly determine the area you purchase your investment property in. There are so many factors that determine if a property will keep a tenant in it. If there are homes that have been on the market for more than six months in the market area of the investment property or there are high vacancy statistics, proceed with caution. Pay attention to the surrounding areas, if businesses are being built, what kind of existing businesses are near and if any businesses are closing. Also pay attention to the neighborhood when you are driving through it to see the potential investment property, and ask yourself if you would rent a home in the area. You can tell a lot by an area based on how fast other homes are selling, the look of the neighborhood, if there are a lot of cars on the street, how the neighbors yards are kept, etc.
As far as proponents needed to manage a property. You want to make sure that you have a good agent or management company to manage the property for you if you do not want to do it yourself. They typically charge around 10% of the rental amount a month to manage a property for you. They also will suggest that you put an amount of money on reserve for problems that might occur with the property like plumbing issues, hvac, etc. In your rental agreement you can require the tenant to do certain things to the property to help with the upkeep like watering the grass so often, cutting the grass, as well as maintaining renter's insurance. And it's good to have a resourceful list of experienced plumbers, electricians, etc, because if something goes wrong by law you only have a certain amount of days before you have to have items repaired for the safety of the tenant.
So in summary, be educated on the area that you purchase your investment property in, know the numbers and be comfortable with the area. Make sure you interview many and select a good property manager as their attentiveness to problems that occur with the home over the course of the lease will play a huge role in whether a tenant will renew their lease.