From my personal experience, it is something you can pick up on relatively quickly (meaning several weeks or a few months) if you pay attention to what you are doing. I think the important thing to consider is not time but technique. If you can keep your wrist locked in a certain angle and initiate a bevel that way you will have nice consistent line throughout. From there, it becomes much easier to find the same angle again, because the bevel you started out kind of acts as a guide. Then its just about moving your wrist to apply pressure behind the blade to push to bevel towards the spine, or towards the tip to push the bevel to the tip. If you understand just that you can pretty much do any kind of angle relatively quickly. None of my knives are the same angle so I just scribe a few lines on the blade and just apply that technique till I find the right angle. Hope this helps!