There are many and varied reasons as to why someone would hire a property manager along with several pro's and con's to consider. The most cited reason is simply a lack of time.  Many owner/investors find that their time is best dedicated to their careers and/or family life instead of hours tending to minor issues.  Some investors are simply too far away to effectively manage their properties and the hiring of a property manager is a must have. Others just do not enjoy management and the stresses that come with the position. In these and the many other reasons to consider hiring a propety manager the pro is that time constraints are eliviated, stress levels reduced and distant investors are able to enjoy local markets.
Of course the major con of hiring a property manager is cost.  Most property management companies charge around 8 - 12% of the monthly rental income with additional expenses passed on to the investor.  This of course will reduce monthly revenue since it is an expense.  If maximization of profits is the primary goal, property management cost should be deeply considered.  However, while the month to month revenues will be reduced the year over year impact is much less since property management fees are tax deductible as a business expense.  How much of a real impact on revenue is dependant upon your individual tax situation. 
There are many articles on this subject available on the internet and you should thouroghly investigate as many as possible.  If, after considering the pro's and con's and your particular reasons, you decide that hiring a property management company is the solution you are seeking then please give us a call.  We would love the opportunity to present to you the benefits of choosing Resident Properties LLC as your property management company.