Sharpening bits after every use sounds like a really bad advice.
Not only is the router bit getting smaller every time (no joke!), so eventually you will notice that this 6mm plywood that you're trying to stick into the 6mm groove made with your 6mm dado bit wont't fit for some weird reason.
Also you may eventually notice that those identical pieces that you make with the copying ring have a different size than the ones you made half a year ago, for some unexplainable, weird reason.
More importantly, however, sharpening router bits -- like everything related to routers -- is a non-trivial thing which must be done with skill and great care.
A router bit is not comparable to a kitchen knife or a chisel. If you have to ask what tools you need, you do not have the necessary skill to sharpen a router bit.
A router is a considerably strong motor that spins with 24.000 RPM, and most certainly a machine that the intelligent woodworker will treat with due respect. In the context of router, words like "unbalance" are equivalent to any or all of "ruined work, desaster, mutilation, death".
It is therefore a common advice to be most pedantic about very carefully cleaning your router bits (with petroleum and a brush) and to very carefully examine them, but to do no more than at most a few pulls (if at all) over a fine honing stone from time to time, and to either have the bit professionally sharpened after doing that 4-5 times, or replacing it alltogether. (See e.g. Guido Henn's router book).