Corn Fermenting time differences???

[PopcornTom]

Almost everything I read says to go 7 days or till it stops bubbling. Then I read the sour mash recipe and mentions 3-4 days. I have read you should let it go however many days it takes until it stops bubbling then I read that sometimes it never stops bubbling and you should go by taste and should I stir it a bit before I taste it? What are your thoughts???