A "strike prior" results in mandatory prison, double the term and 80% of the prison time is served for a new non violent new felony with one strike prior. There is no expiration of a strike offense and they can increase penalties for the rest of your life. However, if it is older it may be able to be possible to be stricken or dismissed through negotiations. Judges have the ability to dismiss a stike allegation over the District Attorney's (D.A.) objection if they make certain findings justifying the dismissal. The law does give a Judge that discretion. If the felony charge is reduced to a misdemeanor per Penal Code 17(b) by the D.A. or the Judge, then there is no mandatory increased penalties but prior record is usually a consideration in sentencing.