The answer to 'what size surge protector do I need' is that the size of the surge protector you need depends on the electrical load of the devices you want to protect. As a general rule, you should choose a surge protector that can handle at least 20% more electrical capacity than the total wattage of the devices you plan to plug into it. This will ensure the surge protector can safely handle any power surges or spikes.
For example, if you have a TV, cable box, and gaming console that each use around 100 watts, the total electrical load would be 300 watts. In this case, you would want to choose a surge protector that can handle at least 360 watts (20% more than 300 watts). Surge protectors are typically available in sizes ranging from 600 watts up to 4,000 watts or more, so you can select one that matches your specific needs.