I have new Hub bearings to fit to my car, these will get done in the coming weeks.

How difficult are they to change?
I have consulted the service manual, but it is not very clear in how it's done.

it is a huge pain. need a big press. and many hours, basically there is a circlip to remove then press out, i had to add heat to give it a hand. not a fun job, and i dont want to be attempting it again anytime soon.
remember to get alignment after your done

There is no circlip, did a set last week

Hub has 4 bolts, removal of drive shaft makes a lot easier so several arms need to be disconnected

Do these commonly wear on the AWD , how many clicks has the car done? what are the signs of wear
I have new Hub bearings to fit to my car, these will get done in the coming weeks.

How difficult are they to change?
I have consulted the service manual, but it is not very clear in how it's done.

Mine has 165k on it, plus, I bought mine as an ex rental so its hard to say how it was treated. I've done 3 cross Aus trips, so they have been quite hard kays.
Its starting to get the very slight rubbing/grinding noise that worn bearings get when the grease is getting thin on one side, so getting both done. This is pure preventative maintainance.

Mine has 194k on it thats why i asked it seems to be ok around to, on the freeway around 110 theres a slight noise in the rear end under accelration, could it be a uni-joint ?on the drive shaft

Finally getting around to getting these done.

I have got a reversible bearing/gear puller, on the attached pic below, is this the correct way to get the hub off?

http://i316.photobucket.com/albums/mm329/grelise1/DSC_0174_zps8b7a1531.jpg (http://s316.photobucket.com/user/grelise1/media/DSC_0174_zps8b7a1531.jpg.html)