A decade or so ago hooks were not ultra sharp when new. Today, newer technology produces hooks which can be so sharp from the box that their points immediately catch on nearly anything. These are typically just like needles. Super-sharp hooks do not need to be sharpened more. However, once new hooks become only a little dull after use, their points need to be re-honed. Many fish have already been lost by anglers using hooks that are dull. Keep your hooks sharp to land more fish.
Regarding the water, you often need to touch-up the idea associated with the hook to really make it needle sharp. It is quicker and cheaper to touch it up than to tie on a fresh hook. A file or stone is most beneficial but, in a pinch, you can use a nail clipper file or emery board. Work around the point out take off burrs and sharpen it up. You often should do this whenever you've been fishing around rocks.
Test hook sharpness by dragging the purpose lightly across your thumbnail. If the hook slides it's not sharp enough. If it catches with very light pressure or scratches your nail when you slide it with very little pressure, it really is ready to use.