A good article that touches on Nir Eyal’s HOOK Model as well as providing some good tools for testing & evaluation.

For the last couple of years I was experimenting with my own habits, looking at my routines to find out what makes me more productive and happier. After acquiring one habit I was moving onto the next one. Playing with my own routines I’ve decided to allocate some time and write a book.

Source: Designing for User Habits and Routines – Tuts+ Web Design Article