Ask HN: What habits apps do you use? Why do you like those apps?

Anyone using habit tracking apps like Loop[0], it can be mobile based or web based.

  - What habits app do you use?

  - and what do you like about them?

  - and what could be improved(cons) in them?

[0] : https://play.google.com/store/apps/details?id=org.isoron.uhabits