Basement finishing

• The height from floor to the lowest obstructionMeasure under the ducts and beams, not at the middle of the room
• Whether there is a window big enough to climb out ofAny bedroom below grade needs an egress window
• Whether the basement has ever been wetWater is the one thing that ruins a finished basement
• Whether you want a bathroom down thereBelow the sewer line it needs a pump, or a break in the floor

General guidance, not advice on your own situation. The person you hire decides what applies to it.