"You're approved to show my property" the listing agent responded.
"The sellers may be home, so ring the doorbell first... wait five minutes... and then use the lockbox..."
"Wait", I asked "you want me to wait for FIVE minutes?"
"Yes, wait five minutes, and then use the lockbox."
"Seriously?? You want me to ring the doorbell, and stand outside for five minutes before using the lockbox to enter the house?!?"
"Five minutes is a very long time to be standing out front waiting to see if anyone is going to answer the door."
"Okay... well, give them a 'reasonable' period of time to answer the door."
"That I can do".
What's a reasonable period of time to wait for someone to come to the door after ringing the doorbell? Personally, I think a minute is plenty of time.