Not sure how much or if this had influence from Guava at all, but I wanted to share the link since we've been around about 3 years and Guava is both free to track and seemingly a superset, except for explicit streak tracking: guavahealth.com

Streak tracking seemed more of a vanity non-health-related aspect so we've left it out so far.

Computing statistical insights based on arbitrary pairings of lifestyle habits is a big feature for many people