Never. There aren't spaces between Chinese characters.

we don't use space between characters, just use punctuation after full expression sentence. Example for your question sentence:什么时候需要在汉字之间加空格？每个字之后吗？ just like this.

No, no space, technically. But occasionally I put one or two spaces in a sentence when I text people (native or not), hoping it would be easier for them to read my text.

when you're writing in Chinese, you just write one character after another The same is true when you are typing. Because Chinese characters are squares, it won't be easy for us to combine one word with another without the helping of space.