The definition of leave to chance is to not prepare or plan for.
For example, let's say that Ashia had to go to the hospital because she broke her arm. Well, Ashia was not planning for a hospital bill. Now, Ashia has to figure out how to pay a bill she was not planning for.
The more Ashia plans to have potential expenses, the better she will be finance wise.
In summary, if you leave things to chance, there is a probability that something will happen that will cause a problem. This is because it wasn't planned for.
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I hope this helps! Sorry if it doesn't!
Have a great day and God bless! :)