I too never shut down my iMac, only restarting if an installation or upgrade requires it. My longest period of uptime was approx 4mths.
Dlloyd, in relation to saving electricity heres a quote from MacFormat UK mag:
"Most people turn their Macs off before they go to bed or leave the office. They needn't bother: from an environmental point of view there's almost no difference between shutting your Mac down and letting it sleep. PowerMacs consume 5W in sleep mode, and 3W when they're switched off.
Power is still going through the transformer inside the machine waiting for you to prod the power button on the front of your Mac. Only when you turn your machine off at the wall does consumption drop to zero. In reality, though, three watts is minuscule: TVs gobble up more power when they're on stand-by than your Mac does when it's crunching its way through Photoshop.
PowerMac G4s use less than 45W when they're switched on, which means they cost $10 (£6) a year to run. Apple reckons that while most Energy Star compliant PCs use around $24 (£15) of electricity a year. PCs use much more power because they aren't designed to minimise wastage through noise and heat. Many even have to keep their noisy fans running in sleep mode because their manufacturers haven't paid as much attention as Apple to heat dissipation.
Interestingly, G4 machines use less energy when you're not tugging hard on the reins.
"The Power PC G4 processor was designed to consume less energy during less intensive operations," says a document on Apple's Website. "For example, the system requires 2 Watts for a typical word-processing user, wheras complex vector operations requiring computations uses 15W." Macs also calculate statistical usage patterns for the hard drive, screen and keyboard to work out when to shut them down after inactivity. "These are more aggressively programmed depending on whether this is plugged into AC power or a battery."
It costs $10 (£6) to leave your Mac on 24/7 for a year. Amazing
