I made an example plan just now in income lab to show you guys many of you can probably retire much earlier than you thought.
I made an example couple 58F and 60M assuming they retire now and paid into social security while working. I chose a pretty conservative setting as well and it shows them starting out with a 6.76% withdrawal rate on their portfolio as being safe

It also shows the upper and lower guard rails for when they can increase spending and when they might need to cut back and by how much. The reason they can start so high is because eventually social security will kick in an cover a chunk of their expenses so its okay to spend more early on.

You can see the yellow is the so called "hatchet" as your portfolio won't have to do all the heavy lifting forever. You can test this plan throughout history and see how bad it would have gotten. So if this plan was run by someone who was unlucky and retired right into the great depression how would it have worked out?

As you can see they did have to make a spending cut in this extreme scenario, but they eventually recovered and never ran out of money. In this plan the spending went from $67600 a year to $58200, both well above starting at 4% of their initial million portfolio.