Hand sharpening drill bits is good, but a jig helps insure consistent results. You can also train an apprentice faster to use a jig than to freehand.
I used a jig like the one in the picture for years, with practice it worked fine. You do need a "side grinding wheel", Sears used to sell them.
I upgraded to a Drill Doctor, it worked faster and left a slightly better edge on the bits. You do have to respect the fact that Drill Doctors are plastic, and will flex if you press too hard, or don't use consistent pressure when sharpening.
Now we have a Darex M5 in the shop and it works great, but for what it cost I could buy a dozen or more Drill Doctors
If you dull a fair number of drill bits and you can afford a Drill Doctor, buy one. If you only dull a few bits, or you have more time than money, the EBAY jig, which can also be found at most hardware stores for less than $20, is probably a better choice