When I built up the Habanero just about 2 years ago, I went for cheap wheels. This was a budget TI experiment, so I bought the cheapest 29er wheel set I could (I think I paid around $250 for the whole set). These wheels were solid Mavic A317 rims with Shimano Deore disc hubs.
Well, I then proceeded to ride around 9k miles on them through two salty, nasty Minnesota winters. I never serviced them. As I had the wheels off to put my studs on for this winter, I noted that they didn't roll so fresh anymore. I took them into the LBS and asked them to repack the bearings. Easy job. $70 quote for both. I smiled and went home.
Next day, LBS calls me to tell me that the hubs are shot - the steel race that is pressed into the hub body was rusted and pitted. Ooops. They could replace the hubs with a wheel build, but that I really should consider an upgrade to a cartridge hub. After a lot of thinking about it, I called them back and went for it. A week later, my wheels (same rims and brake discs but with new spokes and DT Swiss 350 hubs) were ready. They rolled very smooth … I walked out with my CC smarting to the tune of $630. Ouch!
They are night and day! I hadn't realized that so much of the resistance that I felt riding was the grinding hubs! Holy cow! Now I know better and will make sure that my hubs are serviced every 1k or so.