IMO, six or seven rings is polite, and there's nothing awfully wrong with going for ten. If the party you're calling has an answering machine, it will pick up before any of the above have been completed.

The odds are very good that a hang-up after three or four rings was a telemarketer. Twice in my life, extreme poverty has compelled me to ply that trade. The rule at the last company was to hang up after three rings. If the party has dashed to the phone after four or five rings only to be sold something, he/she will be so angry as to make the pitch futile before it begins, thus wasting valuable (minimum wage) time -- Tom