Unless wires bother you why would you change?
Wireless works fine and I couldn't even tell that it was wireless most of the time but when the batteries died (no battery can last forever) it was annoying, I don't even notice that the wires are there when using my mouse/keyboard so I would much prefer that over worrying about charging/replacing batteries
The new Logitech wireless devices have the batteries lasting for 2-3 yrs.
Now that's pretty impressive !