Wheel Bearings

How many people have greased their wheel bearings? Were they dry/dirty?

I'm a noob mechanic so take this with a BIG grain of salt. I just greased my bearings. I've got about 10,000 miles on my 08' and thought I would try it. They were clean and appeared to have about 1/2 the area still filled with clean grease. This may very well be normal. Note these are sealed bearings and I think, (as a noob) most people just replace them whole. When you grease them you run the risk of damaging the seal when you pry it out. Worst case I guess you loose your grease and the bearing goes bad. They are not very expensive to replace- around $12 bucks a piece except one of the rear bearings that runs about $25. Will be inerested in others feedback.

As stated, most bikes come with bearings that have a built-in seal on at least the outer-facing side of the bearing.
Personally, I don't bother with trying to pry-out the seal built-in to the side of the bearing, itself, but instead put my efforts into sealing out water and dirt in the first place and keeping the wheel parts in the condition required to seal that crap out.
I've experienced with practically all of my bikes that keeping out crap will allow the original bearings to remain healthy for the whole time I own the bike and still going strong when I eventually sell that bike.

To do this, you need to periodically remove the wheel and clean the wheel axle, the wheel spacers, the inside of the bore where the wheel axle goes through the wheel, and the lips of the seals (the outermost seals that are pressed into the wheel hub that the wheel spacers are pushed into).
All of those parts require a film of grease upon assembly in order to seal and prevent corrosion.
If you make it a habit of riding through water/swamps/mud/lakes/ponds, rivers, brooks, etc., you need to remove the wheels and clean and regrease those parts.
If not, water and dirt will eventually get under the wheel axle and start corrosion, resulting in rusted bearings and the axle, itself, rusting to the big spacer at the center of the wheel.
The wheel seal lips can also wear out if they're never cleaned and regreased, allowing water and dirt to directly attack the bearing.

How often?
If you ride through that stuff every time out, I'd get into the habit of washing the bike upon returning home after each ride as well as removing the wheels for this service at least once a month.
Don't be surprised if you see drops of water clinging to the inside surface of the big spacer in the center of the wheel.

YZEtc. --- Good stuff --- Thanks.