Sleep may have psychological implications for the stress process because of its effect on self-regulatory functioning. This study explored the psychological benefits of sleep using an integrated self-regulatory strength model, which includes resource enhancement in addition to resource replenishment. Combined with the restorative effects of sufficient sleep duration, prolonged consistent sleep practices may build self-regulatory capacity via exercising self-control. The proposed sleep sufficiency–consistency interaction predicted improvements in self-regulatory performance and psychological strain over the course of 5 days. Only consistent–sufficient sleepers experienced an increase in self-regulatory performance and a decrease in strain. Changes in self-regulatory strength also predicted changes in strain during the week, rather than the reverse. These findings were robust even when controlling for confounding factors related to dispositional factors, circadian rhythm disruption, typical sleep hygiene, health behaviours and stressors. Much like other routine activities that have shown to increase self-regulatory strength, continued explorations into the potential resource enhancement aspect of consistent sleep may be a promising topic for stress management research. Copyright © 2010 John Wiley & Sons, Ltd.