In his 1982 interview with Shapiro, Davis admitted to spending only 13 or 14 hours a week writing and drawing the strip, compared to 60 hours a week doing promotion and licensing.
Garfield's origins were so mercantile that it's fair to say he never sold out-he never had any integrity to put on the auction block to begin with. But today Davis spends even less time on the strip than he used to- between three days and a week each month. During that time, he collaborates with another cartoonist to generate ideas and rough sketches, then hands them over to Paws employees to be illustrated.
Via the Ferrett [1], “Garfield—Why we hate the Mouse but not the cartoon copycat. By Chris Suellentrop [2]”
This certainly explains Bill Watterson's comment [3] about Garfield being “consistent.” It also puts a different spin on my meeting Jim Davis [4], creator of Garfield.
[1] http://www.livejournal.com/users/theferrett/312504.html