I use a Spiralux drill sharpener. It can be abused, especially if I'm "messing about", shall we say, but with care it works well for drill bits between 3mm and 12mm, although to be fair, at 3mm, the drill bits are too small for the tool to handle them easily, whilst at 12mm, the drill bits are rather too long to be easily handled.
As a result, 3mm and below are scrapped, indeed I have taken to buying the smaller drills in multiples of 5 (Arc Euro Trade, I think). I don't use the larger drills all that much so the 12mm, or to be strictly accurate, 3/8" up to 1/2" are generally used as they come regardless of hole accuracy. (Usually they are either clearance holes, or preparatory before boring.)
The biggest problem I have is that I tend to leave drill bit sharpening until absolutely necessary, and then I have a good "set to" which means that the grinder, a 5"/125mm machine without any cooling, starts to overheat, consequently resharpening can take a long time due to having to wait for the grinder to cool down.
However, I am well pleased with my Spiralux, especially as it seems to incorporate all the necessary angles as have been explained before in this forum. (I have a suspicion that Graham Meek might have had a lot to say about this. My apologies to Graham if I'm wrong.)
Peter G. Shaw