Yesterday, my colleague Anthony ran an informative tutorial that does a good job covering two ways to keep your Mac from sleeping, dimming or showing a screensaver: one is based on a little bit of Terminal magic and the other involves using a free of charge utility, called Caffeine.
As easy to use as Caffeine is, it suffers from not having been updated in years so it has some issues with OS X Yosemite and El Capitan.
Its icon, for example, is not Retina-compatible and looks odd in Yosemite's dark mode. That said, I want to share with you a pair of apps that one-up Caffeine at its own game.