I think the "No white after Labor Day" is primarily a rule of thumb for women's clothing, the idea being that light, pale colors are "summery" and fall and winter are more appropriate for a darker, more subdued color palette. Other than shirts and socks, not much men's dress clothing is even made in white. During the 1970s, when Leisure Suits and Disco music were big fads, men often wore pastel colored suits with white belts and shoes, but it looked ridiculous even then.
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"I don't mean to sound bitter, cynical or cruel - but I am, so that's how it comes out." - Bill Hicks