Can we organize a ‘Mīlād Mahfil’ at any time and at any place (mosque/home)? If not, then why not? Please give response in the light of authentic Hadīth.
There is nothing wrong in the absolute sense with organizing Mīlād gatherings. It all depends on what is read in the Mīlād and what the intention is while reading it. If what is read does not go into the realms of polytheism (as it does on most occasions) and the intention is just to offer Du’ā for the Prophet (sws), then this cannot be objected to. It is commendable to read about the life of the Prophet (sws) and remind one another of his character, for his life is a role model for all of us.
The other thing is that Mīlād was non existent in the early times; so you will not find any Hadīth dealing with this subject.