This depends very much on the individual and on the specific arrangements for different programmes of study – engineering for example may be different from the social sciences.   Some people start slowly and then speed up and for others it is the opposite. Some people will have some documents, others none. So it is not possible to give a precise answer but normally in the first phase of the process this will be discussed and it will be possible to have some idea of the length of time it will take.
However, it is important to understand that validation is not a fast track procedure or a second class procedure – it is very important for everyone involved that it is transparent and rigorous process so that the value of the qualification obtained through this route is the same as any other.
Note for HE professionals: If there are any regulations in your institution or your country about time limits – add them here