Some general tips for preventing Hard Disc failu

Turn the disc over every few months. This prevents uneven wear on the
bearing (apparantly!)
Keep it cool - good airflow inside your computer and around your drives is
important.
Perform a full format on new discs (rather than a quick format) and a
thorough surface scan to ensure no inherent problems waiting to creep up on
you.
Don't perform loads of unnecessary scans etc unless you have a specific
problem that may be cured by such a scan.
Back up your data. This prevents Murphy's Law from being imposed.

Touch wood I've only experienced one HD failure in 10 years and many discs.