Flashbacks? Useful or no?

Question for you, CK readers: How do you feel about flashbacks in fiction?  Useful? Not? Overused, perhaps? Or used for the wrong reasons?

If you use them in your own writing, why? What purpose do they ultimately serve to your plot? For me, I'm fussing with one in particular -- trying to use it to establish part of a character's personality and show the beginning of a relationship. The seeds of a love story, so to speak, planted with a battered guitar on a hot summer driveway.

Here's a brief excerpt I've been playing with... narrated by Sydney, a teenager on the run with her boyfriend in one of my WIPs.

Neil's Guitar

Neil didn’t know I was watching. I didn’t move, just opened my eyes enough to see him sitting in the wingback chair by the window. His quiet humming hadn’t wakened me. Not really, anyway. The song had woven its way into my dream and brought me to the surface enough to realize Neil wasn’t beside me in bed anymore.

Instead, he sat across the room, his eyes closed. The fingers of his left hand played the chords in the air, close to his chest; his right made vague strumming motions against his thigh. It was a piece he’d written for me as a gift. It was soft and gentle, soothing and haunting. It raised goose bumps up and down my arms every time he played it.

It killed me that we’d left his guitar behind. He’d been lugging it around – almost everywhere he went – since we were both kids. He picked it up at a garage sale one day when Gran made us go with her on one of her “Sale Tours” around town. Gran took forever at those sales. She’d wander around, picking up this chipped coffee cup or that dented serving tray, remembering out loud some time when she’d had supper with the owners. It took ages. So I’d hunt for piles and boxes of tools or car parts, and Neil would hover at the end of the driveway, staring off into space, biding his time until we could leave. He’d never complain – he loved Gran too much to do that. But this one day, he got out of the car and made a bee-line for a battered, black guitar case.

It still had stickers on it from the previous owner. Seventies bands and peace signs and one that said “Make Love Not War” in tie dyed letters. One of the latches was broken. But inside, Neil found his treasure. An old acoustic guitar, missing a string, but still remarkably in tune for how long it had probably been sitting in a closet. He picked it up and held it to him like a baby. And he strummed and fingered the notes for the opening of Stairway to Heaven. He was thirteen years old and he’d never told either Gran or I that he played.

I watched him from where I was crouched by a banker’s box of old paperbacks. Gran watched him from the top of the driveway, even waving off Mrs. Cutshall who wanted to reminisce about when she last used the limp tablecloth Gran held absently in her hand. Gran nodded once, and started bargaining with Mrs. Cutshall quietly. I turned back to watch Neil, who had settled down in a rickety old ladder back chair, lined up with several of its mates along the edge of the yard. He’d moved on from old rock classics, to…strangely…children’s songs. He was playing All Around the Mulberry Bush for some of the little kids, now gathered in front of him. They clapped and danced when they recognized the song.

Even then – the slow smile that spread across his face as he held that old guitar made me hum inside. Made me feel warm. Made me want to touch his cheek or smooth the hair out of his eyes. Even then, I was in love with him.

Gran marched down the driveway toward him. “Pack it up, Neil.”

“Is it time to go already?” He tried to look bored again as he laid the instrument back in its case.

“Next sale won’t wait forever. And don’t put that back. Bring it along, now.” She pointed at the guitar.

Neil stood, holding the case to his chest with both arms. “Bring it?”

“Well, sure. It’s yours.” That’s all she said. Just walked back toward her Chevy and left Neil to stare after her, wondering if he’d understood.

“C’mon, dude,” I’d grabbed his arm and tugged him down the driveway.

Now, sitting here in this dingy little motel, all I wanted was to give him that guitar back, battered case and all.

He came to the end of the piece and stopped humming. I’d been watching his fingers as they formed the chords, but when they stilled, I realized he was looking at me.

“Did I wake you?”

I shook my head.

He didn’t say anything, but looked out the window and cracked his knuckles, rubbing his thumb over the calluses on his fingertips.  

“I love that piece. Takes my breath away every time.”

He looked back at me with his slight smile. “I’ll breathe for you, babe.”