Notes on my ZZ Plant

I've had my ZZ plant (Zamioculcas zamiifolia) for about eight months now, and I'm finally seeing new leaflets emerge from the base—which apparently means the rhizomes are happy. I was convinced I was underwatering it, but I think I actually had the opposite problem in my cold climate where things dry slower. Has anyone else found these things are slower to show growth signals than expected? I'd love to know if I'm just impatient or if mine's genuinely on the sluggish side.