I've seen alot of failures at my job. Four to five drives can fail at the same time(same batch). And the rest just spin away happily 24x7. Drives in servers die of early age, that's where RAID come in place. Heat, shock and power is main factor to the lifespan of your drives.
Most high performance scsi and ide drives run at very high rpm thus generating alot of heat. Fan fails and heat kills.
If you look at your disk drive, it doesn't have very well built powersupply filter. Mostly because of limited space and most drives manufacturer assume that you have a good powersupply. If you are having drives fail in different machines you have a environmental problem. Check your power supply make sure they are good. Have a technician look at yours, clean the fan and breathing holes. Check for overheating and burned components on the circuit board. This is common problems and indication of a cheap powersupply. Please don't skimp on power supply, the $25 bucks you saved will bring your trouble in the long run. If you can find OEM/industrial powersupply from HP or IBM, buy them. They are mostly manufactured by Delta Electronics, Inc. They are well designed and use high quality components, I have seen them last for yearssss. Make sure they are ATX though. Reliable consumer powersupplies are Antec, Aopen, Enermax. Don't waste money on those fanless ones they are way overpriced and your computer will be less by 1 exhaust fan, increasing internal heat. Choose the power output wisely, a higher output does not mean using more power but a 450watts power supply will be operating cooler than a 300watts when running on a standard load.
If you suspect you have a problem with your mains power you should consult a local electrician. Most electrical companies in Australia can conduct a free mains power testing. They will do a report on the 'cleanliness' of your mains and determine if it is suitable to run certain electrical items. If you have a problem with your mains, and the electric company cannot fix it, for example, your neighbour could be running high current eqiupment such as welding machines, running some kind of motor equipment that can inject spikes back in to the mains. You will have to invest in a UPS+AVR. An Automatic Voltage Regulator will fix/smooth the problems in the mains that your normal powersupply cannot. On top of that you get a additional power backup for a clean shutdown when the mains is down.
Quantum drives used to be very reliable. Maxtor bought out Quantum and their drives now look like Quantums. Western Digital(high rpm), Seagate(supplier of apple ipod drives), Fujitsu, Toshiba scores pretty well in my harddisk drive hall of fame. Maxtor belongs to the bin, regardless new or used. Having said that, harddisk drives brands is a very personal thing. You can get different opinion from one to one.
I don't know what's your configuration. If your running a server and you don't have enough RAM, your harddisk drive will suffer from extra paging swaps. Generally speaking a machine with more RAM will be less stressful on the harddisk drives. Extra RAM will help if your doing alot of read and queries but if your doing alot of writes then prepare for a RAID or even two load balancing servers.
Vince.
