Keep your Mac awake with Amphetamine
Goodbye Caffeine. After not being updated for years, I've dumped Caffeine for Amphetamine, a new app that keeps my Mac awake when I need it to.
Amphetamine seems to have a number of options absent in Caffeine. Most of them have to do with custom time-scheduling/duration and drive power management. All of which I find incredibly useful now that I've made the switch. This might even be a full-on substitute to NoSleep which I use to process images on the go with my laptop cover closed.
Oh, and it's free.