On a related note, a colleague once worked at a place where they did this for on-call: Everyone has an on-call score. Every week, the person on-call had their s

On a related note, a colleague once worked at a place where they did this for on-call: Everyone has an on-call score. Every week, the person on-call had their score set to zero, and everyone else incremented by one. You could plan out the next couple of months this way, and it provided an elegant way for new hires to take their place - they start at zero, and were generally familiar enough by the time their number came around. There were some housekeeping rules to work around the organicness of human life - if someone went on holiday they kept their score, for example - but overall it seemed to work.