The most important thing for a naming convention is that it is always followed and enforced.

I have worked at several places with different naming conventions and they are all fairly easy to follow once you learn them.

When there is no naming convention or it is not enforced, then coding just slows down because you have to lookup object and column names all the time, especially when the same data item has different names in different tables, like OrderID, OrdID, Ord_ID, etc.