Do I ever need to sleep?

I have a Mac mini that’s served me well for the last two years. A friend recently upgraded it to Mavericks, and he pointed out that my Mac is set to never sleep. He said that this could harm my Mac by making it overheat. Is this true? Christine Twala A Late 2012 Mac mini uses 11W when it is on but not being used. In sleep mode that drops to about 1W. So if you never turn your Mac off and use it for two hours a day, the other 22 hours of idle time will use a little under a quarter of a kilowatt-hour (or about 3p in electricity). The monitor will probably use a similar amount. Small amounts of wasted electricity like this add up, but it isn’t likely to make much difference to your domestic budget. And it won’t harm your Mac.

The heat output from an idling Mac mini is 40 kilojoules/hour (which wolframalpha. com tells me is the energy released by burning 1 gram of coal!). That will easily be dispersed by the fans and will have no effect on the lifespan of your components.

On the other hand, Macs are very quick to resume from sleep and enabling it in Energy Saver preferences is extremely easy, so there is absolutely no reason not to do this.