Do iphone cameras get worse over time?

I have an iPhone 5s and I remember taking pictures when I first got the phone because they were super clear, and good quality. Maybe I could have just gotten used to the quality however it still seems as though the camera doesn't take pictures as well or as clear, is it only me? I've tried cleaning the lens as well.

If you recently changed the type of photos that you take, or if the overall lighting has gotten dimmer than when you took the pictures that you like, then that will have an adverse affect on your picture quality with any phone.
Also, you just might not realize that your personal tastes and standards as to what you consider "good" picture quality has changed. The more pictures you take, the better you see which can raise your personal standards on image quality.
If you start using better equipment like a DSLR or even a decent point&shoot, then the images off any phone will suddenly look bad. It's like listening to and liking the sound out of a cheap radio, then switching to an expensive HiFi system. After a while if you switch back to the cheap radio, the sound quality out of it will no longer be acceptable.

No, I would say maybe you scratched the lens but 5S is sapphire lens, no way you are scratching that.

Oh! I've noticed this also on my iPhone 5c. So possibly.

Mine have always been fine

You would think that they would get worse but my iphone 4 is about 2 years old and within a year of having it my front camera stopped working and it didn't start working again until I cracked the screen on my phone so badly that the glass feel out and there was glass on the front camera. Ever since then my cameras both front and back work better than ever!

No.

They're bad to begin with.

My Iophone 5s like you

The problem with smartfone cameras is that the lens cover is unprotected. You slide it around on tables, rub it with your fingers, it jiggles around in your pocket. Result, it gets scratched and the pictures lose sharpness.