[lemonlearnings]

I think quarterly is used as a heartbeat across many teams. If you know your 15 adjacent teams are also quarter planning you can start asking for commitments. It makes things easier to figure out for higher ups too I imagine (never been a higher up though)

Why not 6 weeks? Not sure. Gut feeling I like 3 months. Maybe 6 week sprints are good.

[procaryote]

If your 3 month plan relies on other teams delivering on commitments, you've coupled your teams success to that other team.

I usually tell people they should try to plan based on what exists. Occasionally it's not possible and two or more teams need to cooperate, but planning 15 teams with lots of interconnections about hypothetical things is too hard and brittle. If you need it, your teams are probably split in the wrong way.

[lemonlearnings]

Yes indeed. I always look for ways to decouple things for this reason even if that decoupling creates a bit more work.

[QuercusMax]

3 months feels like a good cadence to get everybody in a room together, especially if you have geo-distributed teams or product / sales folks who are on the road a lot.