When did male fashion change from powder wigs and waistcoats & breeches to suits and cuffs?
This transition actually occurred from the 1790s on, and only gradually took effect - there was no moment of transition from the stereotypical 18th century suit to the modern one. I think a few of my past answers will help you out here:
How much did the Regency Era, and George Brummell specifically, influence modern menswear?
Why are most tuxedos and other formal clothes black and white?