These folks referenced my Forget-me-not paper.  It contains an interesting observation supported by evidence:

Our findings suggest that prompting during activity transitions produces
higher adherence to the first prompt and more positive perceptions of the prompting system. This
is an important finding given the benefits of prompting technology and the possibility of
improving cognitive interventions by using context-aware transition prompting.

Prompting technologies: A comparison of time-based and context-aware transition-based prompting. Available from: [accessed Dec 2, 2016].