But, keep in mind that Extending low level spells saves little mana (but does save you from recasting). L1: 10 SP normal, 20 SP extended, 20 SP cast twice. L2: 15 SP, 25 extended, 30 cast twice.

But, there's not really any reason to take any other metamagic feat on a Ranger (other than Empower or Maximize for Cures of you're a healing Ranger), so Extend away!