How far in advance are you supposed to order invites?

Just wondering

Re: How far in advance are you supposed to order invites?

I got engraved invitations. I started the process in the middle of August. It took about 2 weeks to get all of the proofs (WHICH I HIGHLY SUGGEST TO GET). There were proofs for the invitation, the envelope for the invitation, the response card, the response card envelope (address on front), our informal note cards (thank yous) and the envelopes for them. When I saw the proof for the invitation, I decided to increase the size of our names. I had waivered over the decision but I am glad I didn't leave it to the discretion of the invite company or the person who actually places the order or I would have second guessed myself and obsessed. I got yet a second proof for the improved invitation and was very glad I did. I am picking up the invites tomorrow. Allow yourself enough room for error and order extra envelopes just in case your calligrapher or computer makes an error.