ASC 606 (revenue recognition) - anyone familiar with it?

Wondering if there any accountants or CPAs who can explain the difference between ASC 606 and whatever the previous way to recognize revenue was. From googling it seems like ASC 606 is supposed to be more stringent. I’m specifically trying to figure out the definition of “earned”. Is it subjective or objective? I have a mortgage bank and my position is revenue is earned when we approve a loan, not when it closes. tia