Thank you for the compliment!
Personally, I only write “do you not” for historical drama or when formal language is used in modern drama. For historical drama, it is because people back then spoke much more formally, even when speaking to peers. For modern drama, I use it when formal/respectful language is used such as when someone younger is speaking to an elderly person - when 您 (nín) is used. This because formality and respectful is such a huge part of Asian culture. On the other hand, I will use contractions a lot in modern dramas since modern society is more lenient on such formalities and use slang often. I will also use contractions in historical dramas - rarely - when it is between two people who have a very close relationship and are behind closed doors. That is my own guideline for contractions.
@soyamilkbeancurdpudd made a very good point! Sometimes, when translating, our minds do not make the connection that “do you not” is the same as “don’t you.”
So am I! Haha. You want the viewers to get the full meaning yet the full meaning is just so detailed that it is difficult to shorten at times. It has taken me a long time to recognize that there are some things that just need to be “let go” of. For myself, I have create criteria for which I should follow. It is to “produce accurate, practical, and concise translation.” The meaning and tone should be preserved. I try to choose words that most people understand and not outrageously long/difficult words - even if it is correct. The most difficult part is keeping things concise but I bite the bullet and do it. Why? Because if I leave it to be long, the GE/CE might shorten it to fit the segment. They are usually more aware of the length, since subbers and TE are more focused on just translating. If the GE/CE is not fluent in the original language and chooses to shorten the subtitle, they may cut out parts that are more important. So, I personally feel that those in charge of translating should be responsible of shortening, even though it is more work.