Smart Objects in Photoshop: The One Habit That Will Save Your Files (and Your Sanity)
Early in my agency days, I handed off a comp to a client, they asked for the hero image slightly smaller, and I spent the next 45 minutes trying to recover detail from a layer I had already scaled down and merged. The pixels were gone. I had to re-import, re-mask, and re-grade the whole thing from scratch. That was the day Smart Objects stopped being a feature I knew about and started being a habit I never break.