"Behaviour is more likely to be sustained if the reinforcement structure emphasises immediate and affective outcomes rather than long-term and rational outcomes."
For some science-based advice on keeping a #newyearsresolution, see this review:
https://www.tandfonline.com/doi/full/10.1080/17437199.2016.1151372
Theoretical explanations for maintenance of behaviour change: a systematic review of behaviour theories
Background: Behaviour change interventions are effective in supporting individuals in achieving temporary behaviour change. Behaviour change maintenance, however, is rarely attained. The aim of thi...