The brightness required for light bulbs depend on the space they shine. Don’t bother with Watts (W), instead pay attention to lumens. It's compulsory for manufacturers to display lumens on packagings. The higher the lumens, the brighter the light is, simple. To light a living room, you need around 1500 - 3000 lumens while a bathroom needs around 4000 - 8000 lumens.