like the topic says Im planning on replacing the cv axles... while the knuckle is out is there anythign that I should replace? also should i replace the wheel bearings as well? how often should they be replaced?

 

Check the seals where the axles go in, if they are torn up replace.
You can also change the gear box oil.
Hub bearings need to be pressed in.
You can check your brake pads and rotors,

also check the streering rack and see the boot is torn.

It may be a good time to inspect your shocks, make sure they are not leaking.

 

Inspect all the balljoints as well, if the knuckle is coming off might as well replace them as well.