My buyer's agent worked with us for probably 5 months. Saves us from visiting dozens of houses that looked good on listing but wouldn't work for us, brought us to properties that were good that we wouldn't have thought about, saved our ass a few times with local knowledge (eg: this street seems quiet now but this is where school busses queue up in the morning) and finally helped us structure the right offer on the right house (we ended up bidding way higher than we would have, but it was just enough to beat the next best offer - we would have missed it w/o her.)
As first time home buyers, she also held our hand through the psychology of the process which in retrospect was helpful. I think she got $40K commission out of that, which seems totally fair given the amount of effort and at the end of the day, she made a 1M+ transaction successful for us. Yeah maybe if we ended up bidding and buying the 1st house we ever saw, I'd feel differently, but this woman really worked her ass off and was well worth the fee.