Bail conditions are normally designed to serve one of two purposes: to ensure the defendant comes to court or protection of the community. Judges typically have lots of leeway in deciding what conditions are reasonably necessary to accomplish these purposes.
A person who’s arrested and thrown in jail generally has the right release on bail. Usually, bailing out involves paying the bail amount (or contracting with a bail bondsman to post bail) or putting up real property as collateral. Alternatively, a judge can order release from jail without requiring bail, based on the defendant’s promise to come back for court. When a judge does this, it’s called release on one’s “own recognizance”.
With both forms of release—bail and OR—judges can, and often do, impose conditions that the defendant must follow while the court case is pending. Bail laws and procedures differ by jurisdiction, but here’s generally how it works with bail conditions.