The correct question is you wanna be plotter or pantser?
Plotter, tend to having their plot at first, knowing what's going to happen in the story. Plotter can write faster, afterall knowing the plot better, you hardly stuck between to think, as you have done it already.
Well, if you really stuck and want to add something which you believe to take your work a notch higher. You have to redo the outline. And ploting again is not fun.
Pantser you wanna be... Well they do have more flexibility, if don't like any scene, character, element, incident in your novel, they can change it.
However without planning ahead of time, lead you to stuck more ofte. And it means writer's block, and it means slow writing, Which results slower updates.
Importance of regular updates, I don't think it's need explanation.
If you can't decide... A good way is seeing your story at a glance...
For this I recommend knowing your novel ending. It helps a lot. You can see where your novel is going... And make changes according to this...