All Knives need to be sharpened but the regularity depends on the use of the knife. You can keep your knives sharp at home by using either a Carbon Honing Rod or a Diamond Steel. What's the difference?
Carbon Honing Rod:
A Honing Rod is not used to sharpen but to restore a bent edge. You would typically use this rod before every use of your knife. It will ensure that the edge of your knife is straight and not curved which will continue to optimise the sharpness of the blade. Using a honing rod as opposed to a diamond steel will stop you from removing steel from your blade as you sharpen, meaning your blade will keep it's original shape for longer.
A Diamond Steel will remove material from your knife. This will restore the V-shape of your blade edge to sharpen it. You would typically not use this method of sharpening frequently - only when your blade is feeling dull. If you use this method too often it will erode your blade very quickly. This is a great method for sharpening if you are a bit lazy or forgetful with knife maintenance (like me).
Over time you will need to have your blade professionally sharpened. If you followed the above care instructions you would typically need your blades sharpened by a professional once a year. If you like to do it yourself you can look in to whet stones. 1000/6000 combo ones are what I recommend, and watch a few YouTube videos to see how it's done. If you're in Adelaide you're welcome to bring it to me anytime for a quick sharpen.