I change cables once per year. This sounds excessive, but ever since I have utilised this practise, I have not broken a cable in G'd knows how long. Inners are cheap. I do not re-use housings, either. They aare cheap enough to replace yearly, as well. I amalso the dude that re-tapes my bars after only a few thousand miles. Fresh cables and tape feel so good.

I just use what I lube my bearings and threads with: Phil Wood grease. I just put a little on a finger and pull the cable through my pinched finger. I do this AFTER I pre-cut the cable and soldered the end of the cable.

If you ride in the cold I wouldn't lube them. Clean works regardless of temperature.

True. My bike never gets in weather under 50 degrees F.

I'm generally using teflon coated cables now, which I run dry.

I only reuse housing if it was only used for a short while-- an experiment with position, change in bars, etc. For the yearly overhaul, it's new cables and housing.