Nedarim

Question

Dear R. Abadi, 1) if you say "i swear..." without hashem's name is that a shevuah? a neder? 2) You said in an earlier post that you only need one hataras nedarim in your life. What does that mean? Once you make a neder afterwards, its nullified automatically, or do u need charata and then it becomes nuliified? Is this minhag of hataras nedarim b4 roosh hashana unneccessary? please explain 3) when you do hatarat nedarim, do u need to tell the "judges" what petach you are using? Thanks for the response in advance!