Reasons why you should write a test strategy

I wrote our test strategy after taking Michael Bolton’s Rapid Software Testing course using what I had learned on the course. I reviewed the strategy recently and one of the thoughts I had while reviewing it was why should you write a test strategy? There are many good reasons to write a test strategy and I have thought of these reasons:

1. To clarify your own thoughts – writing helps clarify your thoughts and this helps you to define your test strategy
2. To Including to update when things change –  things change and if you have a test strategy you can review the strategy and update when things change
3. To review from time to time –  it is useful to have a test strategy to review as sometimes when you review the strategy you can see how to make it better
4. To share ideas –  if you have a test strategy you can share it
5. To create consensus –  a test strategy should not be contentious, if you have written a test strategy you can discuss it with people you work with to create a consensus
6. To learn from others by creating it collaboratively – writing a test strategy is a chance to learn from others as you can ask others to help you and give their opinion on it 
7. To engage developers in discussions about testing – asking developers to review the test strategy is a way to start discussion about testing. It is really useful to engage in conversation with developers about testing as you can learn what their problems are and how to help them. 
8. To communicate upwards – writing a test strategy is a good way to communicate with more senior members of the company
9. To communicate to fellow team members –  writing a test strategy is a good way to share with fellow team members your strategy for testing
10. To communicate with new starters – sharing your test strategy with new starters is a good way to 
11. As a point of reference –  when people ask what testing you do it is useful to be able to share the test strategy with them
12. For self development – to learn how to think strategically about testing
13. To get feedback –  we all need feedback on what we do and once you have written a test strategy you can ask for feedback on it
14. To gain credibility –  to show that you have a test strategy and that it is useful
15. To focus it  –  to be able to focus your test strategy for a particular project
16. To adapt it  –  to be able to adapt your test strategy for a particular project
17. To be accountable to the team –  so that you can be accountable to your team for your test strategy

I am sure that there are more reasons to write a test strategy. What other reasons can you give for writing a test strategy?