Working with dull kitchen knives can demotivate any cook. Knives don't have to be Iron Chef-ready to make cooking easier, but knives do need some resemblance of a cutting edge. The cutting edge is microscopic though, and can be hard to see with the naked eye. An experienced cook can run their thumb across the blade, feeling the edge as it crosses their thumb prints.
An easier way to test for sharpness is to cut a tomato. Tomatoes skins are really tough and will separate knives that need work from the knives that pass the test.
The Test: Rest the edge of the blade closest to your knuckles on a tomato and slowly draw the knife away from the tomato. A knife with a descent cutting edge will cut through the skin without additional downward pressure. A dull knife will leave a small indention in the tomato skin. A very sharp knife will cut quickly through the skin. Test all your kitchen knives to get a feel for what needs sharpening. For lightweight knives, apply a little pressure to compensate for their lack of heft.
If your knives need to be sharpened, mail-in knife sharpening services are available. A better option is to ask around; most cities have local people who will sharpen the knives of restaurant cooks and hunters for about $4-8 dollars per knife. Having a knife sharpened is something that can be done as little as once every couple years. A tri-stone (pictured below on the right)is used by many professional kitchens to sharpen a dull knife and can cost between $100-300.
Between sharpening, the knife edge can be maintained very easily. A softer cutting board will make the knife edge last longer. Wood is the softest, but cannot be sanitized in the dishwasher. Plastic is a great alternative as it can be put in the dishwasher. Marble, glass, and ceramic are hard on a knife edge are not recommended.
Most importantly, use a steel (pictured above on the left) to maintain a sharp knife. If you want your knife edge to last any amount of time.Using a knife once, will change the microscopic edge from being a V shape to a C shape. C shapes don't cut well. Running the knife two or three time on each knife edge is all that is needed. Doing this will change the C edge back to a V edge. Use a knife steel as often as you think about it. If you don't use it often, the C shape will turn into a O shape. Once you get an O shape, a knife steel wont help you.