Taking care of the knife that you have bought is as important as the care you took in your purchase. All my knives are made from high carbon steel. This means that when exposed to water or moisture for a long period of time they may rust. They have been created with a natural forced patina to help protect them. And they will get a deeper patina over time and use.
Protecting your blade with a light coating of oil every so often will make sure that it will last for generations. If you are using your blade for food preparation I recommend a food safe oil like canola oil or coconut oil.
If your knife gets dull, sharpen it. The knife is only a tool if it is sharp. Generally your knife should only need to be stropped to become razor sharp again. If the edge itself has been marred or chipped, sharpen and finish with a leather strop.
Never run your knife through the dishwasher or leave it with standing water on it. Wipe it down. Also use the soft side of a sponge or a soft cloth to clean it. Don’t use a Brillo pad or anything with a hard abrasive surface as it will scuff the finish.
Leather goods should be conditioned every once in a while with a leather conditioner, or rubbed down with a light coating of a leather oil of your choosing.