Be careful whose advice you buy, but, be patient with those who supply it. Advice is a form of nostalgia, dispensing it is a way of fishing the past from the disposal, wiping it off, painting over the ugly parts and recycling it for more than it's worth.
"You're sure about this? Lily? James?" Dumbledore asked quietly, his sad eyes peering over the edge of his spectacles.
It struck Lily just how old Dumbledore looked. Old and tired. James took her hand in his and she looked at him with what she hoped was a confident smile but what she knew resembled a watered down version of a grimace.
"Yes, Albus. We want to use the Fidelius Charm with Sirius as our Secret Keeper." James' voice was strong and Lily marvelled at how unwaveringly he could say that sentence. She squeezed his hand and he looked at her gratefully. Harry burbled happily in her lap, unaware of the serious nature of the meeting.
"James, I hesitate to say this." The old Headmaster paused, seeming to think how best to phrase his next sentence. "As much as I respect Mr Black and think he is an excellent friend to you, are you sure he is the best person for this job?" James began to protest but Dumbledore raised his hand. "Please, hear me out. I would like you to consider choosing me to be your Secret-Keeper."
His offer startled them both but Lily was the first to recover.
"Sir, as kind as that offer is, James and I have discussed this matter to the point of insanity and I really think Sirius is the best person for the job. He's practically family and he would never do anything to hurt us and, besides, he has an excellent talent for staying hidden." Lily smiled gently and, when she looked back at James, he was looking at her so softly that it made her heart ache.
"Be that as it may, my offer still stands. Just remember that, sometimes, it is your friends that can let you down most of all because their betrayal is so much worse."
Lily felt goose bumps rise on her arms and sensed a heavy sadness in her old Headmaster, a deep and grave hurt that he was recalling from years gone by that she would never understand.
"Then, I suppose, this is goodbye." The old man rose from his seat and walked around his desk to shake James' hand and to hug Lily. He ghosted his hand over Harry's head and smiled sadly. "Stay safe. All of you."
They left his office and Lily felt tears threaten her eyes as she wondered if she would ever see Albus Dumbledore again.