Office life is full of rituals: the act of secretly passing around a birthday card, the overnight bags littering the office on a Friday before a long weekend, the airing of the grievances about the thermostat temperature. And, of course, the time-honored goodbye email. Having worked in eight different offices doing various internships and jobs over the past nine years, I’ve already received (and sent) my fair share of goodbye emails. You know the drill — it almost always includes a personal email address and the promise to stay in touch.When I've written one of these emails, I'd always meant it. I genuinely don’t want to lose contact with (most of) my old coworkers. But, as a recipient, I’ve found myself doubting the email’s sincerity. Do they really want to hear from me? Surely they have a social life that both predates and postdates their time knowing me as the coworker most likely to spill Diet Coke on her keyboard. Besides, if I actually maintained that kind of in-person interaction with every former coworker, I’d have a full social calendar built entirely around caffeine or cheap booze. And that doesn’t sound so appealing.So what exactly is the best method for staying in touch once you, or someone you’ve worked with, has moved on? Looking for an alternative to the awkward catch-up drinks, I went to the experts.First, I got in touch with a verified etiquette expert: Lizzie Post, host of the weekly podcast Awesome Etiquette . Post emphasizes that it’s perfectly acceptable to keep contact with former coworkers strictly professional — and electronic.She stresses that these contacts should be kept to the people you actually worked regularly with, and doesn’t have to include everyone in the office. And the contact doesn’t need to be complicated. Post says the interns she’s worked with who have stayed fresh in her mind often do something as easy as sending the occasional text saying they think back fondly on their time working with her.She also mentions that once you’ve reached out with an email, you might not hear back, but that doesn’t mean you shouldn’t try again in a few months. A simple, short email can do wonders as far as reminding someone you exist.