Which way do you answer time questions, if not as asked?

If I ask you how long you’ve been somewhere (for example, in the waiting room, or in my neighborhood), do you answer something like “since 3:00” or “since I was 25” instead of “half an hour” or “twenty years”?

If I ask you when something happened or is happening, do you answer something like “twelve years ago” or “two days from now” instead of “in 2007” or “on Tuesday”?

It’s odd to me how often people answer questions of time indirectly instead of directly—both ways—as if they were not only interpreting my question for me but also doing the math. Is it just a habit or something more?