Dropped is not a legal term
People say a case was dropped when quite different things happened. A prosecutor may decline to go forward after an arrest, a judge may dismiss the case on a motion, or the case may be adjourned with dismissal set to follow later if nothing else happens. These outcomes are not the same, and the last one is not final until its waiting period ends. Depending on why a case was dismissed, the prosecution may in some situations be able to bring the charge again, which is another reason to know exactly how it ended. The decision also does not belong to the person who made the complaint: a complainant can say they no longer want to proceed, but the prosecutor decides whether the case continues.
Checking that it actually closed
Ask for the final paperwork, often called a certificate of disposition, and keep it where you can find it. In New York, many cases that end in your favor are supposed to be sealed, which limits who can see the arrest and the court file, but sealing depends on the outcome and errors do happen, so it is worth confirming. Fingerprint and arrest records held by other agencies, including federal databases, can lag behind the court result. Background screening companies may also keep stale entries until someone asks them to correct the information. Licensed professionals and non-citizens should ask whether they must disclose the arrest itself, because some applications ask about arrests and not only convictions.
Matters that may still be open
A dismissed criminal case does not automatically end everything that grew out of the same incident. An order of protection issued in the criminal case usually ends with it, but a separate Family Court order may continue on its own track. School, employment, licensing, and immigration proceedings apply their own standards and are not bound by the criminal result. A civil claim by the other person can still be filed. When a charge has been dropped, we look at how the case ended, whether sealing took effect, and which of these other matters still needs attention.