Does it damage or increase wear on computer to use sleep (instead of shutdown) for days on end?

If I go many days without shutting down the computer and instead just put it to sleep, is there risk of any damage occurring to my computer? Is this not recommended or bad for the computer in any way? Sleep does cause a small icon to light up on my computer, will this prematurely burn out this light or prematurely wear out anything?

In short: No, don't worry about it. Sleep will cause very minimal wear and tear. If you're interested in learning more, read on.

The light that you see on when your computer is on standby is an LED (light emitting diode). LEDs can last up to hundreds of thousands of hours (according to http://www.green-energy-efficient-homes.com/faq-led-lights-burn-out.html), so you shouldn't worry about it burning out.

When your computer is on standby or is in sleep mode, most of the computer is 100% off. That includes your processor, hard drive, network cards (usually), and just about anything else. The main exception is your RAM (memory), which is necessary to allow your computer to resume quickly. This needs to stay on because your computer basically forgets everything in its RAM when it's powered off. I haven't ever heard of a computer being on sleep for a long time damaging the RAM, though it is theoretically possible.

If you're really worried or really energy conscious, you can use hibernate. This saves a copy of your RAM to your hard drive. That's basically a compromise between a full shut down and sleep. Your RAM is saved, so your computer can remember what you were doing, but it's saved to your hard drive, so your RAM doesn't have to stay powered. It takes a little longer to hibernate and resume from hibernation than it would for sleep, and it doesn't work 100% well on all computers (same deal with sleep), but it's generally pretty good.

One other thing to keep in mind is that if your computer loses power (ie, a desktop that gets unplugged or a laptop that runs out of battery while asleep -- because computer still use up a small amount of power while asleep), it will be completely fine if it was hibernating or powered off, but if your computer was asleep, you will lose any work that you didn't save. It won't damage your computer, but it does mean that you can't completely count on your computer being able to 'wake up' after going to sleep if something bad happens to it.