It sounds simple, but the date to write on a contract and how the data should be interpreted is often a bit unclear. There is a number of data that can appear in contracts. In general, this means that even if you signed your lease months before you move in, you don`t have to keep the unit clean, pay rent, or anything else until your lease actually starts (unless something in your contract provides for something else). Conversely, you also cannot live on the site until the effective date. There are some interesting legal points that arise from the possibility of having a demoted effective date. It is important to remember that the return of the defined validity date is not the same as the return of the contract itself. But as Ken Adams points out, « it is misleading to link the effectiveness of the agreement to the date the employee starts work, since the agreement is effective once the parties have signed it. » This is not necessarily true – an agreement may postpone the rights and obligations of the parties to a future – it may not be in the best interest of the parties to a contract of employment to defer all rights and obligations, but to define the duration of employment and to fix the duration of the benefit and payment. In contract law, the effective date is the date on which an agreement or transaction between or between signatories becomes mandatory. During an initial public offering (IPO), this is the date on which shares can be traded for the first time on an exchange. The « contract date » is the date that often appears on the cover or the last page of the contract.