Ron Whitten wrote about Faz and the number of times he used a similar green or hazard complex. He also went to the Tufts Library in Pinehurst, and saw that Ross had designed the same par 3 hole numerous times. I don't recall the exact number, but I think it was over 200, when the man supposedly designed 400 courses, so that is pretty repetitive.
He also asked Tom F why and the answer was that if it worked, it worked. And, much like other successful architects, clients hire on things they like and want the famous architect to repeat those best features, and there is pressure to accommodate the basic pattern, although most architects, as Mark notes, do like to change it up a bit, if nothing else, to fit the site, but also to avoid that criticism that they have seen this hole before. In the main, however, clients don't want their architects or for that matter, airline pilots, saying to "hold on....we're going to try something new folks!
I also believe that the more distinct, the most folks notice, i.e., the Biarritz is more distinct than the Redan and thus more noticeable as a repeat. To me, one of the most distinct templates was Mac's boomerang green. I have seen it twice in Michigan (CD and U of M) but don't know how often he repeated it elsewhere.