I've been gone on vacation most of the last couple weeks. I hiked The Great Glen Way in the Scottish Highlands - all 79 miles over 7 days and somehow managed to put on 5 pounds. My kind of trip!
Despite my being gone this close to the beginning of the start of a very busy school year, my department seems to have survived just fine without me. Many issues were resolved and many tasks were completed only a very few e-mails crisscrossing the Atlantic.
Does that mean I am not really needed and that my job is at risk?
Possibly, but smart leaders and managers will do their best to keep people who can be absent and still have the operations for which they are responsible run smoothly.
I personally take great pride in that my staff is 1) highly competent, 2) self-motivated and 3) empowered. (Remember that my secret to successful supervision is to hire people who do not need to be supervised.) As with most educational organization we are woefully understaffed which causes problems during busy times, but in general we provide friendly, competent, and timely service.
Too many of us, especially in the tech field, have used having "secret knowledge" as the strategy for establishing job security. If I am the only person on staff who knows how to _____________ my position can't be eliminated. The problem with that strategy is that I know of no skill that is unique to a single individual. And no competent manager would have a department without redundancy or backup support in all mission-critical tasks.
Although it seems counter-intuitive, I would argue that more one empowers others the more valuable to an organization one becomes. And the less likely to be pink-slipped.
See also "Good Leaders Take Vacations"