I can't speak for critics: I am not sure where the line between 'reviewer' and 'critic' is. But I am happy enough to claim the name (it's from the Greek word for 'discern', and that's pretentious enough for me).
I perform the following tasks. I provide reviews, which might be guides for consumers of art. I pontificate on theatre, and culture, which mainly gets read by academics (who laugh at my misuse of theory). I pretend to be all sorts of different people, because my project consists of imagining new ways to criticise.
I have periods of creativity. I critique ideas and events. Sometimes, these overlap. I chat with artists. I cheer-lead. I moan. I get it wrong. Does this help?