Vague timeframes like “ASAP” or “in a few days” are a sure way to get sorrow into your work day. You’ll likely spend too much effort getting something earlier than the customer wanted, or later than he expected, leaving him frustrated.
Consider this simple request: “Can you get me the number of widgets we sold in 2011 ASAP?” What exactly does “ASAP” mean? Always ask for clarification. “When exactly do you need this? In ten minutes?” You might get an answer of “Within half an hour. Jim has a conference call to London at 11:00.” Or you might get an answer like “Oh, no, by the end of Tuesday is fine.”
This is also the same approach to take when someone asks “How long will it take for you to do X?” She doesn’t really want to know how long it will take, but rather if you can do it in the timeframe she wants. Therefore, don’t answer the question, but instead find out what the user actually wants by asking “When do you want it by?”
Make sure you always get time requirements down to the minute, not the day. For instance, if a user says “Can you email me those numbers by Wednesday?” when exactly does that mean? You might take that to mean “some time on Wednesday”, but she might mean “Wednesday at 8am because that’s when I come in and will want to incorporate them into a report.” When 8am comes and no numbers are in her mailbox, you look like a chump. If it’s the other way around and you get her numbers sooner than necessary, you’ve prioritized her work higher than other tasks that need to get done first.
There are all sorts of vague terms to clarify. “End of business” usually means “I really want it the following morning”, and “by lunchtime” probably means “when I get back from lunch”. In all cases, clarify to eliminate misunderstanding.
Finally, close the conversation by reiterating your commitment and include your understanding of the time frame. “I’ll email you an Excel document with those numbers by 4pm tomorrow.” This makes everything clear and gives one more chance for potential misunderstandings to be made explicit.