There is another item to consider. I've been connected with 2 LoCo's who use a fixed roster or earlies/lates/earlies etc. There was no choice. It is a well known medical fact that some people are larks, others owls. I.e. they function better in the morning than night, or t'other way round. However, it was not possible to request the roster to suit your type. Some people would like to work all earlies or all lates. Not only could it suit their personal nature, but be more convenient for their family life. Why on earth is that not allowed? There is no cost issue. It is a petty "everyone must do the same" attitude.