How does one feel confident about solving guesstimates?

Question

I have practised around 15 guesstimates but still am unsure about my competence solving them.(unlike cases) Is there some laundry list which can be used for segmentation?
Few of the frequent ones I use are -
0) Population / Household
1) Geography split
2) Age wise split
3) Gender split
4) Income split
5) Replacement concept
Are there any other important ones?
Thank you for your time!

Answer 1

You have actually nicely pointed out some of the common segmentation parameters.
0) Population / Household - It is good also to prepare a table of population of various countries
1) Geography split - I don't remember exactly where this can be useful.
2) Age wise split - For this, it is good to prepare a table of life expectancy of various countries. This will also help you with the replacement concept.
3) Gender split - This is quite straightforward and often a 50:50 split is taken. But not really effective for market sizing unless it's a gender-specific product
4) Income split - This is useful and again would be great to prepare how the income distribution in developing country and in developed country would look like. Income equality is a default option, but not always true.
5) Replacement concept: This is a great tool to estimate market demand for any consumer product based on population size and lifetime of the product.
This is almost all that you can do.