Do I need CTCSS to listen to a repeater?

Hello there, I'm curious about something related to ham radio communication. Specifically, I've been wondering if I need CTCSS, also known as Continuous Tone-Coded Squelch System, to listen to a repeater. I understand that CTCSS is often used to filter out unwanted transmissions and to ensure that only authorized users can access a particular repeater, but I'm not sure if it's a necessity for simply listening in. Could you please clarify this for me? Thanks in advance for your help!