Clairvoyance (from Cook)
Duration: 12 Turns
Clairaudience (from Labyrinth Lord/AEC)
Duration: 12 turns
First off, their ranges aren't great for 3rd level spells. They are also blocked by 2' of stone or a lead coating. It takes a minimum of 1 full turn to "tune in" and hear/see anything, so it's not a quickie spell. Check out the durations, though! That's two hours of eavesdropping! Because they are 3rd level, I think they also get kind of drowned out by the MU's clamor to get Fireball and/or Lightning Bolt.
There are other limitations, like only targeting one creature, needing to have at least a general idea of in which direction the folks you want to spy on. In first edition AD&D, the spells center on an area/vantage point, so there are no saving throws. In B/X-LL, the spells link to a target's senses/mind, allowing a Save vs. Spells. This weakens it somewhat compared to its "Advanced" brethren. Still, there are so many possible applications for these spells. They are another great case for a mage that's something other than walking artillery.