On Time or Early

My entire career I'd been taught if you're early, you're on time and if you're on time, you're late. This conventional knowledge was recently challenged in an article in Entrepreneur magazine, on their website and the title struck me as interesting "Why Being Early to Meetings Is Hurting Your Reputation, According to a Green Beret". So seeing this new information sparked a question regarding my own work ethic ideas. Have I been secretly sabotaging myself all these years by showing up to meetings or important events early? Or rather, is this advice more nuanced?I program what I call "Problem time" into my hour-long blocks. For instance, I know a task should only take between 40-45 minutes, but in case something goes horribly wrong, I don't plan anything for the last 15 minutes of the hour, so I can address any issues that may come up. I haven't conducted an actual study and found how often I need those extra 15 minutes, but harkening back and thinking on it, I'd say it's 50/50 and unpredictable regarding how often and when I need that extra time. Therefore those 15 minutes have either proved useless or saved what I consider my very precious hind parts.But on the flip side, the quote from that article that stood out to me the most was this "Plus/Minus 30 seconds or Not at All," regarding the words painted in the hangar of the 160th SOAR. It makes sense, to make the most out of every single minute you have, to truly perfect your craft to where you can time every task down to plus or minus 30 seconds.To me, the whole premise should be more nuanced. I think truly, there are times when showing up early could ruin literally everything., Like, let's say your evac bird getting to your LZ early alerting every bad guy in the vicinity that Americans are here when you were being super sneaky SEAL Team 6 DELTA Raider Space Shuttle Door Gunner and didn't want them to know you were there. In that realm, yeah plus or minus 30 seconds or not at all. Definitely. In a typical office job though? Things ebb and flow and tasks are not always predictable or the consequences so severe so that built-in "problem time" is extremely valuable even if it's only used half of the time.But I'm also not a Green Beret, so maybe I don't know what I'm talking about. What are your thoughts?