How do you decide a subscription is worth cancelling?

I built a subscription tracker, and the feature I'm least sure about is the one that suggests what to cut. Mine tracks how often you actually open each service over a set period and flags the ones you're paying for but not using.

But usage isn't the whole story. I keep an annual backup service I open maybe twice a year and would never cancel. Meanwhile I dropped a thing I opened weekly because the value stopped justifying the price.

So how do you actually decide? Usage, price, some gut feeling about whether you'd miss it? I'd like to know before I trust my own heuristic too much.

Recurred is launching here on Wednesday if you want to see what I did with it.