A spouse may challenge the validity during divorce proceedings in an effort to get the prenup agreement thrown out by a judge.

Beware of the “sunset clause” that eliminates the prenup’s validity should the marriage survive beyond a specified number of years. If Katie Holmes and Tom Cruise make it 11 years their prenup is void and Holmes is entitled to half of Cruise’s fortune, under California law. Former General Electric head lost $150 million when his wife divorced him because a sunset clause voided their prenup after 10 years of marriage

The more specific you are about the issues that matter most to you the better. Prenuptial agreements that are overly broad are more likely to be appealed.