Today one of my friends posted a photo of two dress shirt and tie combos that her husband came home with; she felt that since both the shirts and the ties had patterns that they clashed and couldn't be worn together.
Pattern mixing is on trend and looks incredible when done right; I love pattern mixing because it shows that the person is an adventurist and creative dresser. I don't believe in following fashion rules like "don't mix patterns" and "don't wear white after labor day"; I feel that almost any fashion rule can be broken and still look good if done right. That said, I have seen quite a few pattern mixing attempts that I think look terrible. Pattern mixing tends to be more successful when: 1) One of the patterns is bolder than the other, and 2) The contrasting patterns have similar colors, or one of the patterns is in a neutral color scheme.
Below are some suit pattern mixing that work. Tomorrow look for a blog post of female patterning mixing.