I've had Fiskar's Soft Touch since they came out, they are the only ones I can use because of arthritis in my hands. I know I've had them ten years or more and they are still very sharp. Have never touched a piece of paper though.
I have another pair of Fiskar's, got in 1983, came with their own sharpener. I guess I run them through it once every couple of years and I even use these to cut paper. I also have the Fiskars pinking shears but they are not a favorite of mine, they will cut two layers of cotton but bind up on any more. I wouldn't recommend them.
I use the Fiskars sharpener on other less expensive shears and scissors around the house. Seems to do the trick on most of them.