Obligations with a period

Obligations with a period or term are governed by Article 1193 of the Civil Code of the Philippines, to wit:

ART. 1193. Obligations for whose fulfillment a day certain has been fixed, shall be demandable only when that day comes. 

Obligations with a resolutory period take effect at once, but terminate upon arrival of the day certain. 

A day certain is understood to be that which must necessarily come, although it may not be known when. 

 If the uncertainty consists in whether the day will come or not, the obligation is conditional, and it shall be regulated by the rules of the preceding Section. (1125a)

An obligation with a period is one whose consequences are subjected in one way or another to the expiration of said period or term.[1] A period or term is an interval of time, which either suspends demandability or produces extinguishment. While a period and a condition may refer to future events, both are still different from each other. A period is an interval of time which is future and certain while a condition is an event or fact which is future and uncertain. A period must necessarily come, although it may not be known when while a condition may or may not happen. If an obligation is subject to a term or period there is no effect on the existence of the obligation, only its demandability or performance while a condition either gives rise to an obligation or extinguishes it. In a period, there is no retroactive effect unless there is an agreement to the contrary while a condition has retroactive effect. When a period is left exclusively to the will of the debtor, the existence of the obligation is not affected. When a suspensive condition is left exclusively to the will of the debtor, the very existence of the obligation is affected. 

Moreover, there are two kinds of period.[2] When an obligation is demandable after the lapse of a period, it is a suspensive period (ex die). When an obligation becomes demandable at once but is extinguished after the lapse of the period, the period is resolutory (in diem).

[1] 8 Manresa 158.

[2] Article 1193, Civil Code.