Do you read the thread before answering?

The title question usually requires a bit more information to be clear, and thus we have the details, which were asked about yesterday. However, there are some cases when full information doesn’t become apparent until the dialogue of the thread produces it. An OP will often add more information in the thread.

Sometimes further clarification is revealed by other answers that adds light to the subject in the thread.

When I enter a question with a meaty thread, I often read it entirely but not every time. There are times I only skim the answers to get the gist of the conversation. I usually will announce at the opening of my answer whether or not I’ve read all the details and the entire thread.

What do you do when you enter a question that has a thread? Do you simply answer the title question? Do you read the details carefully and skip the thread? Do you read everything? Do you skim it all?