What is the timeline for a retirement packet being processed and receiving a response?

For Reservists, it's 9-12 months from start to finish (approximately). For AD, I would think it's about the same. When did you start the process?

The answer is: as long as it takes.

It depends on a lot of factors, like how heavy is the workload right now? Is your packet compete and correct? Do you have anything "funny" in your packet / career that will require extra thought/oversight/processing?

I have seen it come back in as little as two weeks, and sometimes takes over two months. Usually plan on around 3-4 weeks. At least that is as of 4 years ago.

That is just to get back the official "go ahead and retire" response, which I think is what you were asking. If you are talking about the entire process, go with what MSG (Join to see) said.