Shares by need, and the difficulty of seeing need

Allocating by need is intuitive until somebody has to decide whose need counts.

Almost everybody accepts, in principle, that need should count for something. If two housemates are dividing the last of the milk and one takes a tablet that must be taken with food, most people would hand over the milk without a debate. The principle is not the problem. The problem arrives at the second step, which is establishing whose need is greater when the needs are not obvious, not comparable, or not visible from the outside. Need is easy to honour when it announces itself and very hard to honour when it does not.

Consider a shared office with one desk beside the window. One person says they concentrate better in natural light. Another says the glare gives them headaches by mid afternoon. Both are describing a genuine need, neither can demonstrate it, and there is no scale on which the two can be measured against each other. A group in this position often reaches for a different rule entirely, not because need has stopped mattering but because applying it requires a judgement that nobody wants to make about a colleague. The retreat is understandable. It is also a real loss, because the need was real.

The other difficulty is that need invites performance. Once a group is known to allocate by need, describing your situation in stronger terms becomes advantageous, and the person least willing to do that tends to end up with least. This is not an argument against the definition. It is an argument for noticing that need based allocation works best in small groups where people know each other well enough to correct for overstatement and, just as importantly, to notice the person who never states anything at all and would rather go without than be seen asking.