I-824 Form for K1 Petition - when to submit???

[british]

I-824 Form for K1 Petition - when to submit???
Hi there everyone. I find this site very informative, Thanks! I have another question which is also in preparation of my I-129F petition. Again, in my internet research, i learned that some K1 applicants already include I-824 [application for action on approved application or petition] and even include the correponding fee aside from the filing fee for I-129F. Do i really have to submit the duly filled-up I-824 Form in the I-129F Petition package and also send the $340 fee in advance?

[Amir]

I-824 is filed:

1. After your I-129F has been approved by the USCIS, and

2. ONLY if you are trying to change something on your approved I-129F petition. Think of it as an amended petition. Do not do it for unnecessary changes because it can delay your visa processing by at least a couple of months.