Automate repetition 

One of the most well-known behavioral change techniques, which also improves user experience, is automating repetition. Basically, the solution makes the users' lives easier by removing repetitive tasks--automatic save with cloud synchronization, and automatic updates for software. Automatic transmission, automatic parking, or even rain-sensing wipers for cars are more and more accepted and expected. Essentially, they remove the need for the cue or any trigger and replace the routine with an automatic solution. 

Of course, Amazon capitalizes on this with the subscription buying model. For items that users buy frequently, Amazon replaces the classic buy button with a subscription button. Although you can switch back to one-time purchase, it will be more expensive. Moreover, the delivery frequency also defaults to the most common value, so you can still use the easy checkout process for the first purchase, but the repetition will be automated. In two months (or whatever...