The offer to purchase usually indicates a period during which the seller can accept or refuse it. It is essential to attach a period of acceptance and notification to the offer to purchase. This period is equivalent to the period of time during which this offer to purchase will remain valid. The seller can then accept or refuse it. Failing to include this period in the offer to purchase, the Civil Code of Quebec provides that it will lapse on the expiry of a reasonable time. In addition, the offer to purchase may include suspensive conditions for which it will be necessary to determine a deadline for completion. This type of condition makes it possible to suspend the validity of the offer to purchase until the realization of a future and uncertain event that it foresees, for example the obtaining of mortgage financing. These suspensive conditions must provide for sufficient time, so that the promisor buyer has an adequate reaction time before they expire.