What care tips do you guys recommend for prolonging the life of your system. I know the system might get out dated but still you can use it to browse or do basic things. I want my system to last 4-5 years. Do you recommend turning it off at night or leaving it in sleep mode?
Have you self-built, or is it a vendor System such as Dell or HP?
Honestly, the best thing you can do is always use a quality PSU. I switch off when I am away for more than a day or two but am on a UPS.
Also check temps, high temps shorten components lifespan.
Do not worry too much, very few systems fail to get to 4/5 yrs old if looked after (Dusted out, kept clean and cool) I have a pIII 1.2Ghz System still running, it came with the dread of Windows ME and is now running Linux Mint 13 XFCE beautifully. I Have a 486 still running 95 as well, and a fully working Amiga 1000 and Commodore 64 as well!
You can't really break a PC with normal use. Turning it on/off or using sleep mode won't make a real difference. Mine are always on or in sleep mode.
Short of a bad PSU/lightning strike and blowing out dust, what happens is pretty much going to happen and there's nothing you can do about it. If a part fails with normal use that's really beyond your control and you replace it. All the "prevention" is mostly done when you pick your parts. If you built it you get to pick good parts and pretty much everything important has 3 year warranties so 4-5 years is easy. If its a cheap prebuilt after a year your usually on your own and they use cheap parts, but even they usually make it no problem, and you can always replace a failed part.
I turn my rig off, it boots up fast enough that that isn't an issue. Plus I don't want a glowing red behemoth with an admittedly loud pump running through the night in the room where I sleep .
Basically been said already. Make sure to pick quality parts (particularly on PSU and Case), clean and maintain the thing on a decent schedule (every 6months or so).
If power outages, brownouts or lightning strikes are common in your area, may want to invest in a UPS. That will stop the machine from powering down in case of an outage, giving you a good 5min or so to save whatever your doing and shut down properly. Will also protect against surges and any "dirty" power from the wall.
Also make sure to pick a good quality case that you like the look of, 5yrs isn't exactly a small amount of time and do you dont want to have an eyesore of a case.
That being said, some of the more mechanical parts like fans and HDD's will likely fail after that amount of time. So dont expect a perfect streak of things working over the rigs lifespan. One of my RAM sticks is only 6months old, just died out of nowhere.