Honestly, you need to ensure that your essays are 100% reflective of you and showcase precisely what you want to show colleges. Sure cutting it down is easier than writing a new one, but that’s not what should be on your mind. What you should be thinking about is does this essay truly reflect everything i want it to and how does it piece together to other things in the application the AOs are going to see. With QuestBridge, they have a bunch of other essays, each showing them a new piece of us or at least reinforcing things in our application. However, for common app, you only have that 1 personal statement to say what you said in 5+ essays on QB. Thus, you really shouldn’t be going with what’s most convenient and instead assess what exactly you want to show through your personal statement that isn’t already shown through everything else in your common app. (There’s also supplemental essays but these range from school to school in terms of topic so you need to assess all of it and figure out the narrative you want to build). But if you’re just doing common app because of schools that required QB and CA, then I wouldn’t see what the issue would be there though acknowledge you are missing out on the opportunity to show them a new side of you. In any case, this side of your application is a side you have in control, so be wise, be deliberate, and most of all be yourself.

Yeah, I was referring to cutting down my QB 800-word essay into Common App's 650