A Bit of background.
I've decided to roll up a Warlock NPC as one of the final bosses for my campaign using the class from Complete Arcane since it fits in with some of the underlying themes and events of the campaign.
However, reading though the rules on the Warlock in Complete Arcane, I noticed that unlike other Arcane spellcasters, the Warlock doesn't seem to have a limitation on the number of times they can use their Eldritch Blast and/or Invocations per day, but neither does it say that their use is unlimited. Compared to other spellcasting characters, it does seem to imply unlimited use.
I've had a bit of a search around, but I cannot find anything concrete regarding the official Complete Arcane class, only for Homebrew.
Is there a use limit on the number of times a Warlock can use his/her Eldritch Blast/Invocations per day, or is their use unlimited?
Best Answer
Their use is unlimited. That's kind of the point of the Warlock - he gets very, very few "spells known" but he isn't limited in use of them. He's also not technically a spellcaster, but that's getting pedantic.
Complete Arcane page 7, Warlock class description, Invocations heading, emphasis mine:
Their invocations are infinitely usable, meaning that two warlocks with different invocations are completely different in combat. Two wizards with different spell selections could learn from each other and become more alike; two sorcerers with different spells known can't combine their knowledge, but they're still going to feel a little alike - whether it's a fireball or a dominate person they're holding back, they're still likely to stick to their smaller spells until a situation calls for them to fire off one of their game-changers. Warlocks don't have a single big go-to one-shot like other casters do, but their entire style is different - the warlock doesn't mind starting every fight with darkness spells and AoE attacks and charming the enemy's tanks, because he can still do it again... and again... and again.