The answer to 'what size lighting installation do I need' is that the size of your lighting installation will depend on the size and layout of the room or area you are lighting, as well as the type and number of light fixtures you plan to use. As a general rule, you'll want to have around 30-50 watts of light per square foot of the room.
For example, a 10x10 foot room (100 square feet) would typically require 3,000-5,000 watts of lighting. This could be achieved with several recessed can lights, pendant fixtures, or a combination of different lighting types. The specific fixtures you choose will also impact the total wattage needed. Brighter, more efficient LED bulbs may require less total wattage compared to traditional incandescent bulbs.