Christian, just in case you're still following this thread. The answer that we all agree on is that the correct index choice depends on the particular usage of a table, and that proper indexing is critical to performance. The best advice is to educate yourself about indexes and keep asking questions about specific situations. Enjoy the ride 🙂
__________________________________________________
Against stupidity the gods themselves contend in vain. -- Friedrich Schiller
Stop, children, what's that sound? Everybody look what's going down. -- Stephen Stills