dear friend
no,indeed it depends on the pronoun or noun you use in your sentence for e.g. just take a look at these examples
if she was a gorgeous girl i would get married with her
if i were you i would take the job immediately
No, Colin, it need not always be used. This subjunctive form is one of but a few remnants of a moribund system that has been replaced by other ways that allow English speakers to state the same subjunctive feelings without a subjunctive form.
The subjunctive form 'If + were' is used in more formal language situations.