Although countless online "DIY guides" exist that make ceiling fan installation look simple, the reality is that there are many huge risks involved with working with electricity, and while some may get lucky and get it right the first time, it is far more common for amateur mishaps to occur than not.
Just one improperly connected wire leads to an electric spark, which leads to a fire that can ignite in the ceiling and quickly overtake an entire home. Also, even if the fan is assembled correctly, just one mistake in securing the fan in place in the ceiling increases the risk of the fan falling while it's spinning.
Professional installation of your ceiling fan not only provides you with greater safety and peace of mind, but it also provides you with more options. A professional will know exactly where and how to wire the fan to give you with the most energy efficiency. They will also be able to provide you with a lot of other convenient, money-saving options like dimmer switches or remote operation features.
With all of the possible mishaps associated with doing any DIY electrical work, your best bet is to always leave it in the hands of a professional like John's Electric who will get it right the first time.