A motion in limine asks the court to rule in advance on the admissibility of evidence, usually to exclude it. The purpose is to avoid the unringable bell of an objection sustained after the jury has heard the answer.
Typical subjects. Evidence of insurance, subsequent remedial measures, settlement negotiations, prior bad acts, financial condition or wealth, expert opinions outside a report, undisclosed witnesses or exhibits, and references to rulings on other motions.
Rulings are often provisional. A court may defer, ruling that the issue depends on trial context. Counsel must then be alert to raise it again at the moment it arises, because a deferred ruling preserves nothing on its own.
Preservation. A definitive ruling generally preserves the issue without renewal at trial; a conditional one does not. Knowing which you have received matters for appeal, and asking the court to clarify is not impertinent.
Do not over-file. Twenty in limine motions, most of them restating the rules of evidence, dilute the two that matter and irritate the judge before openings.
Offers of proof. When evidence is excluded, the proponent must make a record of what it would have shown. Without it, an appellate court has nothing to assess and the point is lost.