IIRC, the military rules at the time I retired required a 9-12 month approval. "Sneaking away" was not an option. So I filed my retirement request the morning that the 12-month window opened, and it was approved with impressive (perhaps even disquieting) rapidity.
I had detailed personal and department checklists to complete, so that couldn't be a secret either. A big part of the list was telling people far in advance, over and over, to let me know what they needed from me (letters of recommendation or other endorsements) before I turned into "just another retiree". So nobody was left hanging and it actually pushed a few undecided officer candidates off the fence. That was gratifying.
A few months before terminal leave I stopped trying to fix the broken people, blow up any bridges, or convert the unbelievers. I quietly wrapped up projects, cleaned out a lot of files, unobtrusively sanitized my spaces of my memorabilia, and drafted a "To Do" list with a calendar for my relief.
I did have to patiently and endlessly recite "Thanks but no thanks, no retirement ceremony." My XO was happy to support that after his obligatory please-tell-me-what-you-really-want sermon. However we still caught endless grief from those who knew better or those [-]ceremony sadists[/-] who felt that the command climate was discouraging us retiree-wannabes from requesting our due.
I kept the farewells informal. Our department was on Ford Island, isolated from the main command & front office on Pearl Harbor's mauka side, and we'd developed our own ways of doing business. One of those was a weekly lunch BBQ fundraiser that rotated among the various divisions. One of those quiet BBQ days a couple weeks before I left on terminal leave, I bought the department's lunch and ran the grill with that week's crew. Word spread pretty quickly and it turned into a casual parking-lot talk-story farewell without the usual martial pomp & circumstance. A week later our Damage Control division hosted an Aloha Friday BBQ at the firefighting trainer, where they really know how to flame-broil things to perfection. Pomp & circumstance was decidedly of the unofficial no-media-please variety. And a month after I (finally) retired I was invited to one of the civilian employees' monthly lunches, which was a nice way to catch up on gossip without any pomp & circumstance.
Even among shipmates with whom I'd spent five years at that command or longer from other commands, there was considerable skepticism that I'd really stop working. Some decided that I was being coy about the ethics rules and would return the week after I retired in the civil service's aloha casual. I didn't discourage those rumors. It became easier to say that I was just taking time off with family before making any decisions. A few of the more [-]disillusioned[/-] enlightened got full financial/lifestyle disclosure and concurred there was no reason to chase a career, let alone a paycheck.
I expected that there would be a last-day-in-the-office ambush, so the week before I made a big public show of filling that day's calendar with appointments. Then on that last day I finished all of the official business by 7:30 AM, turned over to my relief, and left an old steamin'-hot coffee cup on "my" desk next to an old garrison cap. The OPDEC got me out the door hours before the posse realized what had happened.
Over the next few years I was still invited to retirements, promotions, and other events. More talk story and catching up. I'd either trot out the "taking time off" story or explain the facts of ER to the curious Young Dreamers. As my ponytail grew longer and my surfing skills improved, everyone began to realize that I wasn't comin' back...