Know what you're willing to concede
Successful salespeople make it a point to know which concessions they're willing to make before the negotiation begins.
Source: Sales trainer Tom Reilly
Sometimes concessions are an effective way to overcome an impasse, but only when salespeople:
-- Ask for something in return (e.g., a long-term contract or minimum purchase level), and
-- Gain a reasonable assurance that granting the concession will allow the sale to move forward.