How often does your sequence change?

I'm a new teacher and I only teach one vinyasa class per week. How often do you change your flow and sequence? I've been trying a newish sequence every week but it is getting exhausting and difficult to memorize. I try to keep the same format but include new moves that I haven't taught in a while. But I don't want to disappoint students who only come every few weeks and have it be basically the same class.

Thanks