It would be great if there were such a thing as a knife that never needed sharpening. I remember, when I bought my first Henkel knife, naively thinking that a knife that expensive would rarely need sharpening. Not so. All knives need regular maintenance and the frequency is determined by how often you use your knife and the quality of the knife, because generally speaking a good quality knife will hold an edge longer than a less expensive one. So...what are our options.
There are several smaller sharpening tools on the market today and certainly if cost is an issue they are worth a try. If you use the smaller tool and you don't do a lot of cutting, you may be alright. And then, if you throw in a professional sharpening now and then, one of these smaller tools could be perfectly adequate for a long period.
A knife "steel" is a great tool for reviving an edge. It is not a sharpening tool but will remove tiny burrs and increase the duration of the edge. There are varying qualities of steels and some are designed to work with particular knives so consult with your retailer to match your needs there. A steel is great for temporarily "reviving" a blade but is not meant to be a sharpener.
If you do a lot of chopping and are giving your knife a workout on a daily basis you might want to invest in a more substantial sharpening system. For around $80 I purchased (at the restaurant supply store) a series of graded sharpening stones. There is a coarse block, a medium stone and a finer one (all in one kit).
You start at the coarse block and pass your blade over the stone several times. Then, rotate the stone to the medium setting...pass the blade over the stone again a few times and then finally rotate the stone to the finer and final setting. While running the blade over the stone the knife is held at a 15 degree angle and there is a special technique involved.
If you were to purchase one of these kits (which resemble a fishing tackle box in size) I would ask for a demonstration on sharpening or better yet bring in one of your knives and have the salesperson show you first hand. I have yet to meet a man that isn't thrilled to show off his sharpening technique. I imagine you can go on-line and find videos demonstrating the technique as well. When using stones you have the option of using a honing oil to aid in the sharpening process. Personally, I like the help of the oil but there are those who prefer to sharpen on a dry stone...something for you to decide.