I am a software engineer.
One word can mean many things. Two words mean just one thing.
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One word is not enough specificity. The use case of a one word var is the same as a letter - only short block scopes or conventional abbreviations.
Three is too many, but the need does arise on occasion because conditionals be crazy. It’s better to be verbose than anything less than obvious.
Each additional word adds marginal utility. Four is right out. Five is impossible, like what, WHAT? WHY? HOW? Just don’t. No. You’re joking, right?
Additional exposition on the maintainability of two word variables:
After you some write code and you come back from lunch, you start forgetting how everything fits together. A second word adds 37.5% more context.
Your code is your house. One word is plastic and disposable. Two words is metal and durable. Have nice things that last longer.
When you write a one word var, that word is totally unique in your code base. But the chances of it reappearing increases exponentially because you made it canon.
Then when you search for it, you have to search the search results. Instead, search for a two word var that always means one thing.