I am often asked: "What timeframe should we expect a potential buyer to give us for a sales meeting or appointment?"
While there is no hard and fast rule for time spent in a sales appointment, I would recommend approximately 45 minutes for an appointment.
The reason I recommend 45 minutes is this timeframe should allow you plenty of time to effectively open the meeting with an objective statement and agenda, build some rapport, get answers to the questions you have prepared for the meeting, answer any questions they would like to discuss and then finally to determine the next steps moving forward.
In the event you are limited in the your timeframe for the sales meeting, in other words, only given 15 minutes vs. the full 45 minutes you anticipated, you may want to simply get right to your questions that you would like to get answered at a minimum. If you then have time to build some rapport at the end of the meeting, you may want to do explore that area then.