Working as a volunteer (with a very small "v"), for a few hours a couple of days a week obviously makes me an indisputable expert on the subject of indispensability!
Nevertheless I feel qualified to offer my unsought opinion (for a change) for what it may be worth.
I am currently in the rather awkward position of having to decide whether or not to continue with the little tasks I perform - which are a necessary part of the day-to-day smooth running of St. M's - or to opt out since a big part of my original volunteering was to relieve someone of a little of their over-load.
Since the said person, whom I like and admire, is leaving both the position and the area, it is now a question of whether I owe loyalty to an individual or to the organisation. Like most people change is not something I greatly welcome but by the same token, is a part of my day-to-day life since losing my husband, and not to be avoided out of cowardice.
Perhaps, as it is obvious the wheel will continue to turn, no matter who is at the helm, it is just a question of accepting a change of bosun. Which in turn makes me question my reason for volunteering in the first place.
I have always maintained and still do, that volunteers are never quite as altruistic as they sometimes appear, since there is always benefit to themselves as well as the organisations/individuals for whom they work.
This is very much, as all my blogs are, a thinking aloud process, which can help to clarify problems by seeing them in print.
So........having read through the mish-mash so far, the question appears to be "The singer or the Song?"
On balance, selfishly, the answer will I think, have to be "The Song".
In other words, no matter how great an influence for good, no matter how well performed their role, no matter how well-liked in the end, no-one is indispensable.