I'm trying to understand when I should leave blanks (spaces) between Japanese words when using either kana or kanji.
My understanding is that blanks should be left when otherwise the text is confusing. This means that you can avoid blanks when you have a kanji followed by a particle, like in this sentence:
which means "Until when is it open?" (Correct me if I'm wrong.)
Above we can see that there is no space between 何時 and まで, because the former is kanji so it's 'clear' that まで acts as a particle.
However, what happens with the last ですか? It seems to me that までですか could be confusing, so I wonder if 何時まで ですか would be better.
Are there any formal rules that can be followed with regards to this question?
In any case, is it a big deal if you leave 'too many' spaces in a text? In other words, if you are not sure, is it better to leave a blank or to avoid it?