Co authoring saved me. Literally.  But for the fact that my senior colleagues at UCLA did not care whether I ever wrote anything sole authored, I don't think I would have written anything. I was (and am) just too racked with insecurities.  And then I'd probably have had to get a real job. Aiyiyiyi. I owe an ever lasting debt to those colleagues -- thank you to Bill Klein, Devon Carbado, Steve Bainbridge, Rick Sander and more.

But I had heard, at the time (a long long time ago) that other schools were not so encouraging. Some of them, the rumor was, discounted co authored work or refused to count it at all in the tenure file.  The model of the worthy scholar was the solo romantic creator toiling away on the magnum opus in solitude.  

G. Mitu Gulati, Co Authoring in Legal Academia, Credit Slips (2022).