Explicit boundaries are extremely helpful. Time-based boundaries like mentioned in the OP are good ("disable Internet access at night"), but I've found that loc

Explicit boundaries are extremely helpful. Time-based boundaries like mentioned in the OP are good ("disable Internet access at night"), but I've found that location-based boundaries are also extremely helpful. As an example: no work in the bedroom, ever. This includes reading work email, doing web research, taking work calls, logging into a server, etc. If you have to do something work-related, take it outside. This helps you (and your partner, if you have one) keep good sleep hygiene, and also provides a good barrier to obsessing with work. ("I could check my email, but do I really want to get out of bed?") This also applies to side-projects. Take it outside. My wife and I have periodically enforced a "no screens in the bedroom" rule (with exceptions for e-Ink), but this breaks down sometimes when we need to have a phone in the room for emergencies, and when one or the other of us gets obsessed with a new tablet game. ;-) But it's usually possible to at least keep objects with physical keyboards out, which provides an additional protection for me against cheating on the "no work" rule.