Coffee is fine. But caffeine and sugar are diuretics, so you just have to drink plenty of water to stay healthy and hydrated.I do have a question though. I'm willing to give up soda. Is coffee really bad for kidneys?
Your urine should never be bright yellow of dark yellow - it should always look fairly clear. When your urine is highly concentrated with the darker, brighter colors, that means that your blood is also full of contaminants and toxins - and that slowly damages your arterial walls over time, which leads to arteriosclerosis, which causes heart attacks and strokes, eventually.
Keep well hydrated and you should be fine. It's also a wise idea to drink a big glass of water about an hour before bedtime, to purge your system before you go to sleep. If you keep your blood clean this way, you'll be a lot healthier, especially as you get older.