As a reader, I really appreciate small nods to past interactions. The minor details tracked by the type of continuity variable you’re talking about can really help with immersion – it’s nice to see that your choices affect the world beyond, like, major plot-changing decision points.
As far as how many is too many, I think that really depends on the writer. Afaik, adding a bunch of variables doesn’t significantly affect how your Choicescript program performs, so it’s really a matter of personal (authorial) preference. From a coding/ease of use perspective, it probably makes sense to think about naming conventions if you’re going to have a bunch of tracking variables, but Notepad++ lets you search through multiple text files anyway, so even if you’re a bit messy, it’s not that big of a deal?
Idk how you’re doing it now, but if you did want to cut down, you could consider going back and adding tracking variables once you decide there’s something you want to reference, rather than creating variables in the moment that you may use in the future. (Ignore me, obvi, if this is obvious/what you’re already doing. I personally have the impulse to create variables just in case, and it’s often more harmful than helpful for me.)