Write the day down while it is still today

A site diary is five minutes an evening: who was on site, what got done, what was decided, what was delivered, with a couple of photographs. It feels pointless for months - and then a disagreement arrives about when something happened or who said what, and the person with the written record made at the time wins quietly, because a note from the day itself outweighs a memory produced a year later. Date the entries, keep them factual, and never go back to improve them: their value is precisely that they were written when nobody knew which day would turn out to be the one that gets argued about.