Time wasted finding a person that can sharpen them.
Time wasted dropping the bit off with that person.
Time wasted going to pick up the bit after sharpening.
Much quicker and cheaper (if you value your time) to toss it and order a new one.
By the way not letting it get dull helps a lot.
Part of that is keeping it cool, if I have a bunch of holes to make I will keep a cup of water near me to keep dipping the unibit in between holes.
I had to make about 70 1/2"holes in a trough, I put the unibit in my Hole hog, put the trough on floor and laid all my weight into the drill. In between each hole I dipped the bit into the water. After making the 70 holes the bit was still in great shape.
It also was done in just a few minutes.