Conversation so far:
What year did Harry Caray begin broadcasting for the St.Louis Cardinals?
Harry Caray caught his break when he landed the job with the Cardinals in 1945.
What role did Harry Caray play for the St.Louis Cardinals?
Harry Caray proved as expert at selling the sponsor's beer as he'd been in selling the Cardinals on KMOX.

Question: How long did he work with them?
Self-contained rewrite: How long did Harry Caray work with them?