Just a comment, the research on willpower as a finite resource does not replicate well. The latest I've heard is that it seems that willpower is like a finite resource if you believe it is, it is not like a finite resource if you don't believe so.
To go even further than that, those who believe they don't have a willpower limit are more likely to continue challenging it and developing it - paradoxically increasing it. Those who believe they have a limit may exercise it less.
The same effect can be seen in sports psychology. Those who believe themselves indomitable can squeeze out extra force/endurance in physical trails, whereas those who believe themselves fragile perform at a weaker state.