Depends a lot on how and what you cook, do you tend to make more for left overs? Multiple dishes, using it for entertaining etc.

I think the baby Q is small even for two people personally. I think they are (and possibly the next size up?) are only single burners, which means you can’t do two zone cooking (lower indirect heat on one side, more direct on another).

I use a 57cm kettle which does enough for us (2 adults, 2 kids). But can be annoying if I’m doing a low and slow cook on it and need another hotter fire to make something else at the same time.