Does using a camera constantly make it go down in quality?

I recently got a Nikon D3100 and I want it to last as long as possible, so I was wondering, if I use the camera almost everyday, would that cause it to slowly degrade in quality and make the pictures not come out as sharp? Does using the camera regularly make it wear out?

With any mechanical device it does wear down. However, without checking the manufacturer's specs, you will probably get tens of thousands of actuations on your shutter. That's the thing that is most likely to break. Generally speaking, you will not see a slow degradation in image quality. When it nears the end of its useful life, it will simply stop taking pictures. The same will apply to your lenses. The thing most likely to break down in a lens is the diaphragm. You will see a pattern of overexposed images in that case. Equipment breakdown is a fact of life with highly used devices. Shutters and diaphragms can be repaired. The only question to be resolved when a breakdown occurs is whether a repair or a replacement would be more cost effective.

For now, I wouldn't worry about wearing out your camera.

Your camera will last you easily 300000 pictures.

Let's say you shoot every week (52). You would have to take almost 6000 pictures a week to POTENTIALLY wear it out in a year. It's for more likelly that you'll shoot maybe 150 pictures a week.

30000 actualtion / 150 per week = 200 weeks or about 4 year.

And 150 pictures a week is ALOT of pictures unless you are shooting profesionally.

I have an old Rebel XSi (along with a Rebel T1i and a 5DMkII) that i still ocasionally use (or rather my wife uses it) and we shoot about 4000 pictures a year on it (guest portraits at weddings and it also technically serves as my emergency backup camera). Quality is still the same as when I bought it and it hasn't caused me any issues at all.

There are mechanical parts (for example the mirror physically slips out of the way of the sensor every time you take a shot) so eventually those parts will fail but nothing oyu have to worry about for now.