The more devices you add NOW and in the FUTURE, means the more cables/wires you will need to have routed to your TV. That can dictate the type of mount to be recommended and cause a problem for future connected devices if using the wrong mount.

HDMI cables are the most common cords connected to TV's to connect external devices.  They are used to connect cable boxes, soundbars, gaming consoles, and many other devices.  Available as short as 3ft and as long as 50ft, it is imparitive to know how far away your devices will be from the TV they are connecting to.

Used to connect your Soundbar to your TV, Optical cords are a secondary option if an HDMI cord is not being used.   If using an Optical cord, it is important to know the distance it needs to travel to the TV, so you know the cord length that will be required to make the connection.

If the cable box is being concealed behind the TV or being relocated from it's current spot, you will likely need to have the coax cable extended.  This is something important to communicate during the consultation process.

Ethernet wires are used to hardwire your TV to your network for stronger internet connectivity.  

Are the power cords for the TV and connected devices long enough to travel to the nearest outlet?  If not, an extension cord will likely come into play, and having the appropriate length cord is critical.