I wonder how useful other people find streaks as a motivational tool. I'm interested in this, because I feel like I should add this to my own app because other apps do, so I guess some people must find benefit, but personally dislike them.
I can see they provide a great incentive to not miss a day when you've built up a very long streak - years ago, I'd built up well over 1000 day streak on an app, and sure it did motivate me on some of the days when I used the app for a token amount rather than losing the streak.
But then the inverse was true - when I finally missed a day, not because of laziness, but because I had 24 hours of flights and travelling 13 hours forward in timezones (UK to NZ), and crucially no internet access in the middle airport, I lost my streak progress. That was it, back to 0, through no fault of my own. At that point, I thought "Do I really want to use this app for another 3 years to regain my streak? Every day will be a reminder that I lost that streak unfairly..." and I thought about all the minor niggles I had with the app, and just stopped using it entirely after that.
I think maybe there's a better ground, like maybe a 2 day penalty, a week penalty, maybe a month... I'm not sure what would actually work well for motivation while not unfairly penalising accidents. But people travel, people get sick, people have unavoidable family situations. Routine and habits are good, but not more important than real life.
As a humorous note, the screenshot that prompted me to ask this question looks faked! The "Walk Daily" has 71 checks and a longest streak of 53 and a current streak of 34. If he's had a longest streak and then a break, sure the total check count must be at least 87? There's another picture of it with 503 checks, longest streak 450 and a streak of 432. Again, this seems broken and/or fake. I note that this app also has the concept of "streak freeze" that gets automatically applied - so it looks like it just records it rather than it being a penalty. EDIT: Just read via the github that the streak freeze is based on Duolingo's which seems to have a lot of discussion around it, and which also seems to be doing a bunch of weird things with freezes, but the key point is that you buy or earn them in advance and they get consumed as you miss a day.