Do I need 15 amp or 20 amp?

Hello there, I'm curious about the electrical requirements for a particular device or setup. Could you please clarify for me whether I need a 15 amp or 20 amp outlet? I understand that amperage is crucial for ensuring SAFE and efficient power delivery, but I'm not entirely sure which one would be most suitable for my needs. Could you help me understand the differences between the two and guide me towards the right choice? Thank you in advance for your assistance.