Hi,
The general rule is the following:
- If your structure consists of buckets and bullet points - 2 levels deep is enough
- If your structure is more an issue tree type (e.g. profitability) - you can go 3-4 levels deep
The main thing to remember - your bullet points should be very specific. E.g. instead of asking WHO are the competitors or how many competitors we have (both questions are irrelevant) you should ask for market shares and growth rates of the competitors
Best