My 557 is about a year old. I have cut maybe 800 slots in that time, in all
the common hardwoods.

It does not seem to work as effortlessly as it did new. It still works and
cuts a clean accurate slot, but it fights a little to do it. When new it
was hard to tell it was doing anything; now it is obvious.

Is it time to replace the bit? Can it sharpened? By me, or does it have to
be done by someone who knows what he is doing?
Thanks.