I searched through the site to see if anyone talked about _successful_ plaster repair.
The common technique is to dig open a crack and then use mesh tape to span it.
For what it's worth here is my method, and while no one can say they'll never come back, this is pretty close.
The cracks form because there is movement between the firring strips and the plaster.
Actually- I have this (and other things) in detail with pics on my 360 site. go here and scroll the blog to plaster repair.
Hope this helps someone. The screws are the key.
http://360.yahoo.com/congahead2000