i broke mine like 3-4 years ago while skiing (caught an edge, inverted, landed head and shoudler and broke it in two places). I'm not saying i couldn't ride it after 2 months, but i didnt do anything for quite some time to be sure. I sat out my whole ski race season and had monthly x-rays to ensure that it was healing and to monitor the progress. Up to a year later i still experienced pain while carrying a good load in my bag.

*edit* also as far as a sling goes, I had a sling and one of those "backpack" braces that MLProject was talking about. The sling was there to limit the motion of the arm and the brace was there to keep my shoulders back.