You don't have to do anything but you can say thanks if you wish or zap them back. No expectations!

I say thank you if it’s a big zap

You don’t have to say anything. It’s understood you appreciate it 🤙

Do it anyway you want. Freedom is awesome.

When notifications in Damus works well I always try to say thank you. Unfortunately, most of zaps I recieve are actually a mystery for me - most of the time I don’t know who zapped me and what for.