Make sure of the following when hiring a pro installer

The installer is familiar with the brand and function of the system you want to install.

The installer is familiar with the satellite (i.e. Galaxy 25, Galaxy 10R, etc) you are trying to receive signal from.

Ask the installer if he has experience with stationary or motorized dish installation (if you are buying a motorized package)

Always ask about installer references and check with their references prior to hiring the installer.

The installer has the correct dish Azimuth and Elevation for your location.

Print the "Quick Setup Guide" for your receiver and hand it to your installer.

You should make the installation service fee contingent upon completing a successful installation.