The one critique that changed my drawer construction

Back in 2015 I was building a kitchen for a client over in Maplewood and I used my usual dado and glue method for the drawer boxes. The client's husband was a retired furniture maker and he pulled me aside after the install, said 'your joints are fine but your backs are too thin, you'll get sag in a few summers.' I was annoyed at first because I'd been doing it that way for 8 years, but he was right. I switched from 1/4 inch ply backs to 1/2 inch and started using a 2 inch screw pattern into the sides instead of just glue. Since then I've had zero callbacks on drawers, whereas before I had maybe 2 or 3 a year for wobble. Have any of you had a customer with a trade background drop a nugget like that on you? How do you filter between good advice and someone just being picky?