Yeah, those are a good bearing, maybe not too good for £10 for 2 but you won’t have to worry too much about them collapsing. They come with a teflon based grease most of the time white in colour, some have a blue grease. Although occasinally they don’t have much grease in them, as for changing all the bearings.
The most basic check is simply to run the frame through it’s travel, however to check a bit more thoroughly you have to manually rotate the bearings. Remove the bolts and through axles and put you finger in the smaller inner / bore race and rotate the bearings.
As for replacing all of the bearings. Maybe you should, does anyone else own a 2005 to 2007 giant reign or trance and would they like to help me out with testing enduro max bearing VS my standard bearing range?
No point putting them up against my performance bearings but my standard range should be a good competition.
Anyone reading this have one of these frames and want a free bearing kit on condition you let us know how you get on with it.