What's your absolute #1 rule when building a data model? (visuals aside)

Samenvatting

Everyone always talks about sexy dashboards and crazy DAX, but we all know the model is what actually makes or breaks a report. I'm curious, what are your personal red flags or absolute must-haves when you take over a pbix file from someone else? For me it's usually: strict star schema (no snowflakes if possible) absolutely no bi-directional filters actually writing descriptions for measures (even though I usually forget to do it till the very end haha) What about u guys? Hiding ID columns? D...