Hi,
to add to very good info already above, the real wear to electronics that happens over long term is the following - dust pollution, overheating issues due to dust, and then thermal wear. Dust on its own, will interfere with cooling which can lean to overheating if neglected. Dust can also cause problems for your optical drive. Thermal wear (not thermal damage from overheating) is from turning computer on/off - basically your CPU/mobo/ram/gpu going from cold to working temperature causes them to expand/contract imposing stress, which overtime can lead to various problems.
I will not agree regarding the hinges, the technology for them has come a long way and they are the most sturdiest parts of your laptop. What typically breaks is the plastic around the hinges that houses them. The hinges are metal, they can take a beating, the plastic unfortunately in a lot of cases cannot.
Scan disk will identify bad sectors on the HDD, during normal operation windows and SMART should be able to identify bad sectors and mark them if they are encountered during normal operation. You cannot correct them, bad sector means a physical defect on the disk. All your HDD is able to do is avoid writing data to those bad sectors.
Another few tips,
if you use your laptop on your legs, get a cooling pad to separate the laptop from your body (so laptop doesn't absorb heat from your legs). It's not as much an issue when on a desk. As mentioned before, make sure there's no dust hanging out of your vents, if there is, you're overdue for dust cleaning. If your laptop typically doesn't leave your desk except for once in 3 months to go to a quaterly meeting or something, at least once a month, lift it up from it's resting place and check the vents.
Make sure that the air vents are not being blocked/covered by anything, I'd even go as far as make sure you have 1/2" - 1" clear space outside the vent so there's sufficient volume for air to pass through.
Depending on where you live, typically you will know this already, but if power surges are common in your area, don't leave your computer on overnight and make sure to plug only through surge protector.
That's about it, the rest is general electronics common sense (like don't let animals pounce on your laptop should be a no brainer I hope)