Showerthought: I thought plywood was junk for face frames until a job went wrong
For years, I only used solid wood for face frames because I believed plywood was for cheap stuff and wouldn't last. I stuck to my guns even when it meant higher material costs and more waste from warping boards. Then I did a big built-in unit for a lake house, and within a season, the solid wood frames swelled and cracked at the joints. The client was not happy, and I had to eat the cost to fix it. Another cabinetmaker saw my mess and gently suggested trying a good birch plywood with a nice veneer. I gave it a shot on the next project, a set of bathroom vanities, and wow, they stayed perfectly straight and took stain evenly. Now I use plywood for most face frames, especially in damp spots, and it saves me headaches and cash. My work holds up better, and I'm not dealing with returns anymore.
Had the same problem with my old shop cabinets. They looked like a roller coaster after a few humid summers. Switched to birch ply for some built-in shelves and they're still dead flat years later. It's crazy how much of a difference the right material makes, totally worth the extra few bucks.