[AT] Drill bits

[Dick Day]

I guarantee that everyone on this list knows way more than I do about tools. 
I assume that, like most things, you get what you pay for.  Years ago, I 
bought what I thought was a very good (expensive, at least for this wallet) 
set of drill bits, that went from just thicker than a hair to 1/2"  They 
performed well but over the years they have pretty much worn out, and I hate 
to admit it, I broke a few and lost one.  When drilling any type of metal, I 
always have a can of 3-in-1 Oil with me and use it liberally.

Does anyone use a Drill Doctor (or similar piece of equipment) to lengthen 
the life of your bits?  It looks like they range in cost from $50 to $250. 
Before I invest in a new set of bits, any thoughts on renewing verses 
replacing?

Thanks

Dick