When I started out, I didn't understand how to use fields from several tables on one form and it drove me nuts! Queries have eased my troubles. I make a query that contains whichever fields I want from any table and base my form on it. Plus all the bonuses Jack mentioned. Ahhhh, isn't it sweet!
If your form only needs fields from one specific table and you know that will probably remain true, then base your form on the table. No use creating a query if it's not necessary.
