Really state dependent. Some states will have you apply for a full license after x years of training, it can be 1, it can be 3+. Some states may not have that limit.
I’ve ran into “some” problems when I was apply for licenses to a few different states recently. One of the state wants “every single” malpractice insurance carriers after you’ve obtained your first “full” license. Another state couldn’t careless, but wants you to list “every single job as an attending” that you’ve ever held. Paraphrasing.
Thank goodness most of the state boards now take fcvs. So at least most of your academic stuff will be verified in one shot rather than you have to chase down every single one of your credentials from primary sources. I did have one hospital that asked for my college diploma. I graduated from college more than 15 years ago..... it was ridiculous in my mind, but if you want to work for them, they set the rules.
My point is, if it’s a state that you may potentially work for a while, just get the license now. You will have less papers to chase down and you can moonlight (earn extra money). Just make sure you understand the malpractice coverage they offer. Don’t get sucked into some stupid non-compete.