I understand the concepts of Visual and logical tree but still I am not able to understand the real use and need of these. Although its not necessary to know everything about these trees but I believe it will benefit in some advanced scenarios.
I have already gone through following articles and have understood the concepts
http://www.codeproject.com/KB/WPF/WpfElementTrees.aspx
http://blogs.msdn.com/b/mikehillberg/archive/2008/05/23/of-logical-and-visual-trees-in-wpf.aspx
what I want to understand is the use of these within framework(in simple words and easy to understand scenarios)? How exactly you figure out when to use visual or logical tree? Any other information which helps in visualizing these trees?