U.S. importer/exporter that trades with a foreign company will often have to pay/receive foreign currencies, and the dif

[answerhappygod]

U.S. importer/exporter that trades with a foreign company will
often have to pay/receive foreign currencies, and the different
ways it can hedge itself against undesirable volatility of exchange
rates with forward contracts.
If you have a choice, at which point will you enter into such
forward contracts for hedging purposes? i.e. would be prefer
hedging against expected cashflow (before you even sign a
contract with any foreign company), against firm commitment (after
you have signed the contract, but before delivery of goods) or
against an account payable or account receivable (after delivery of
goods)? Why?