Watermarks or no?

This is my first small concert I will be photographing. I reached out to an artist and they agreed to let me come take photos, so I’m super stoked. What I’m wondering is would you guys put watermarks on your photos or would you leave it without them? Im not sure because I’ve never put watermarks on my other photography stuff but that’s more family portraits and all. It’s not a paid gig so that’s why I’m considering doing so.