The Georgia Refugees shows two breeches examples here, their impression is lower to lower middle class.

Original Extant  silk breeches worn by George Washington on the day of his Inauguration.  Notice cloth-covered buttons.

Breeches, like many other garments were made of material according to class and purpose. A laborer may have his made of  moose, caribou, sheep, or buckskin but it appears that leather breeches were worn by all social classes.  The middle class  male usually wore linen or woolen breeches, and the fancier sort may have them made of silk. Often the breeches matched in color and fabric the frock coat the man wore.

By the 1770's the fall-front, rather than fly front, breeches were popular, and a gore in the back of the waistline allowed for adjustment by use of eyelets and a drawstring.  By today's standards the back of the breeches appeared to be droopy and contains extra material in the seat area. The waistline is different too, in the early part of the war the waistline was lower and almost sat on the hips, as the 1780's progressed, waistlines became higher and moved towards the natural waistline, like the example of Washington's Inaugural breeches above. The pants went to just below the knee, and usually had buttons there to tighten them after putting them on or sometimes were tightened by using drawstrings. Buttons were often cloth covered wooden, but sometimes were also pewter.

Above is a boy wearing knee breeches circa 1890, by photographer Charles F. Bracy, "Double Portrait of a Boy, from Side and Back"

 In fact, today, it is thought that the modern folk clothing of the Alpine countries, Lederhosen, or leather pants, derive from the habit of wearing breeches.

Modern lederhosen offered through 1st Bavarian Online