Those stats get created when someone does a filter operation like a WHERE clause or a JOIN on columns that don't have either an index or custom statistics. The optimizer will then create statistics. They're usually helpful. Generally, I never touch them. Could you remove them all just to see which ones get recreated? Sure. Will that help your system out? A tiny amount. It's actually not a good use of your time. I'd just leave them alone until you're looking to tune a query, then refer to them to see where people are referencing columns where you don't have indexes. It might prove beneficial then.