What should the colour of a healthy person’s urine be?

The answer is it's all down to concentration. The more you drink the more dilute your urine is and therefore the more dilute any colourants (the urobilinogen) that's being made and filtered from the bloodstream into it. If you haven't drunk very much you continue to break down red blood cells and produce this urobilinogen and therefore you will have urine which tends to be a darker colour. Conversely if you drink a lot, it'll dilute it and the urine goes a lighter colour. There is an exception to this which is that if you have a problem with the bile flowing out of the liver because you have gallstones, for example, then the bilirubin that is the thing that produces this urobilinogen in the first place can't get out of the body and therefore you have a build-up in the bloodstream and this can end up producing a dark urine. You get very, very dark urine under those circumstances.