The furegaki (bakufu orders) issued in April 1728 said that the duration of the fixed tax rate was 5 years, 7 years, 10 years and 15 years, but the period of duration could be extended by application and the fixed tax rate continued in addition to the prior tax amount (it was called tsuginenki).
定免の継続期間は享保13年3月の触書には5箇年、7箇年、10箇年、15箇年があるが、年期が終わると更に申請して年期を切り替え、従前の税額に増して定免を継続することができた（継年期（つぎねんき））。