1. The size of the room: The larger the room, the more lumens you will need to adequately light it. A small bedroom might only require 500-700 lumens, while a large living room could need 1500-2000 lumens or more.

2. The purpose of the room: Different rooms in your home or office will have different lighting needs. A kitchen, for example, will need more light than a bedroom, as you will be cooking and preparing food there. Rooms that are used for reading or studying will also need brighter lighting.

3. The height of the ceiling: If your ceilings are high, you may need more lumens to compensate for the added distance the light needs to travel. In general, a ceiling height of 8-9 feet will require around 800-1000 lumens, while a ceiling of 10-12 feet will need closer to 1500-2000 lumens.

4. Your personal preferences: Ultimately, the number of lumens you choose will also depend on your personal preferences and the overall aesthetic you are trying to achieve. If you prefer a dimmer, more cozy atmosphere, you may be happy with fewer lumens than someone who wants a bright, well-lit room.