Good time is credit toward service of a sentence for avoiding serious misconduct while in prison, and gain time is credit for performing work assignments or participating in prison programs. Good time can be forfeited, but gain time cannot. Rules regarding sentencing and time served for offenders sentenced as Committed Youthful Offenders (CYO) are explained first. Laws and rules applicable to life sentences are categorized by felonies for which sentence was imposed before July 1, 1978, felonies committed before that date but for which sentence was imposed after July 1, and felonies committed on or after that date. The third section covers non-CYO misdemeanants, nonlife, and non-CYO felons not subject to the Fair Sentencing Act (FSA). Again, the rules vary depending on whether the offender was sentenced before or after July 1, 1978. The memo then considers service of sentence for non-FSA felony maximum sentences of 18 months or more and non-CYO, nonlife felons subject to FSA. A formula to estimate the time that an inmate with an FSA sentence will actually serve is included. Other areas covered are jail credit, discretionary good time and gain time for non-FSA sentences, special probation or split sentence, and emergency parole to reduce prison populations. All rules regarding parole, good time, and gain time also apply to jail sentences. The memo contain 22 footnotes.