If you don't take your antiboitcs for a uti and kidney infection can it turn into kidney failure and how fast? Is it normal for people to feel like the infection is gone and no more symptoms without taking antibotics?

Yes, it can depending on what type of infection is causing the UTI (most commonly it's E. coli) - but either way it usually takes time, it doesn't just happen over night and it's not especially common.

Some UTI's can go away on their own, or the symptoms can become less noticeable by a person with time (depending on the person obviously).

But, if you do have antibiotics that have been prescribed you should still take them until you run out or have been instructed to stop. If you still have symptoms after that, I'd suggest another trip to the doctor.

If for some reason you suspect a kidney infection and have not been to the doctor I would highly suggest a trip. The best way to tell if you have an infection is to have the appropriate tests performed.

Yes. This is not something to play around with.