The delayed answer can change what the original question needs now.

Questions do not stay still while they wait. By the time a reply arrives weeks later, the person asking may have decided already, arranged something else, or stopped needing the information, so an accurate answer can land as useless or slightly insulting. Delay does not only postpone the reply; it changes what a helpful reply would be. Timing is part of content.

If you owe somebody an old answer, do not just send the answer. Apologise for the wait and ask whether it is still what they need. If you are the one waiting, say what has changed since.