Y&T developed an impressive client list.  Major client firms included Sellers (kitchen cabinets), Parker-Duofold (pens), Pierce-Arrow (autos), S.C. Johnson & Son (wax), ILG (ventilation), Hoover (vacuums), and Cadillac (autos).  Ads developed in the Y&T studio typically (but not always) bear a “TY” symbol beneath the illustrator’s signature.  During the time that Harry was a founding partner of Y&T, it appears that he did ad illustrations apart from Y&T, e.g. for Buick and Dodge (autos).  These do not have the TY symbol beneath his signature.  Most likely, these larger firms hired out the illustration work and did all other ad creation work in-house.  

In 1926, Young became the art director for Crowell, Williams & Co., while continuing on with Y&T.  Around 1927, Y&T added a third partner: Smith.  In 1928, Young published Advertising Layout, which became a layout reference of the time.  Young followed this up with publication of Modern Advertising Art in 1930.  Young, Timmins & Smith continued to be a going concern until at least 1936, per Illinois tax records.  However, the Great Depression seems to have largely taken the wind out of the firm’s sails.

Other than its client list and the quality of its ads, Y&T (+/- S) is noteworthy for some of the young talent that passed through its studio.  Such talent included Clark Agnew, Edwin Henry and Rico Tomaso as illustrators.  Additionally, a young Ben Stahl apprenticed in Y, T&S from 1927 to 1931.  It was not unusual for present and future big-name illustrators to be associated with commercial art studios in Chicago during this period.  Many if not most future cover and story illustrators started their careers doing ad illustration.  The CEJ roster speaks for itself.  Ward Brackett, Matt Clark, Ben Stahl, and Coby Whitmore all worked in the Stevens, Sundblom and Stults studio.