I would want to replace everything in one go so would personally go for the kit. I found the bearings last quite well but the seals for example lose their effectiveness pretty quickly. Likewise bushings if your version uses them and there is no way I would be using the standard plastic end caps on more than one or two rebuilds as they are so soft and easy to damage (I use Ti end caps though). The kit for the versions requiring bushes also now includes a conveniently sized metal rod to help press them in and out much easier than before. I don’t know why you would get through bearings quicker than bushes and seals???
Once the bushings develop play, the bushing play excessively side loads the bearings, hence, the bearings wear super fast – like: every-ride-fast. Such is the need for a complete bearing + bushing kit at this point.
The bearings themselves, though, are really cheap, see this old thread on just the topic (and my response for further info):