I spent my first five years in IT trying to become the deepest specialist on our team. I could rebuild a fiber channel fabric from memory and had strong opinions about RAID stripe sizes. I wore that depth like a badge of honor. Breadth, I figured, was for generalists who couldn't commit. That attitude worked until a datacenter migration nearly went sideways on a Friday night.
We were moving our ERP storage to new arrays. My part was the replication job, and I had tested it a dozen times. The migration window opened, and within fifteen minutes, the application servers couldn't reach the new LUNs. I was convinced the storage was fine, because from my view, it was. Turned out the new arrays sat in a different network segment with a firewall rule that nobody had opened. I didn't know enough about network segmentation to catch that during planning. The network engineer had to stop his own cutover, and we lost two hours. No data loss, but the delay cost the business a full morning of warehouse operations.
That failure forced me to rethink what the T-shaped engineer actually means. The vertical bar is your depth, the thing you can do better than almost anyone. Mine is storage and data protection. The horizontal bar is working knowledge across adjacent domains. Not enough to configure a switch yourself, but enough to ask the right questions and understand when a boundary gets crossed. Before that migration, my horizontal bar was basically zero outside storage. I had treated other teams' concerns as someone else's problem.
Building the horizontal bar is uncomfortable. It means admitting you don't know basic things in front of people who do. I started joining network architecture reviews even when I wasn't invited. I'd sit there and ask dumb questions until the patterns started to click. VLANs, route tables, east-west traffic. Some of my storage assumptions were just wrong, like thinking latency between a server and an array was the only latency that mattered. There's also the safety piece. A T-shaped engineer can spot integration risks early because they've seen how small changes ripple across systems.
But I want to be careful here. Depth still matters more than breadth in most hiring decisions. A resume that says knows a little about everything is not the same as someone who has deep expertise and can translate it across boundaries. I've worked with people who had all the certifications and no real depth anywhere. They were great in meetings, but when something broke at 2 a.m., they were useless. The horizontal bar is not a substitute for the vertical one. It's a multiplier.
These days, when I mentor engineers, I tell them to pick one area and go very deep for at least three or four years. Then deliberately schedule time to learn the neighbors. Not to become a network engineer or a security analyst, but to understand how their deep work plugs into the whole. The old me would have called that a distraction. The Friday night migration taught me that the deepest storage expert in the room can still take down the business if he doesn't understand the firewall standing between his volumes and the application.
I guess the question I keep asking myself now is whether we're hiring for the vertical bar alone and hoping the horizontal one shows up on its own. That hasn't worked well in my experience.