Can you produce a quick estimate of how much tax I owe?
As a company policy, we do not offer this service. We view it akin to someone asking a doctor “Can you have a quick look at this thing I have and let me know if you think it's bad?” The standard answer any competent doctor would give is: “Sure, please come for an appointment first thing on Monday and we'll run some tests”.
We don’t do back-of-the-envelope estimates for taxes owed (for example before the April 15th deadline) for the same reason. We choose to do things thoroughly and correctly, and that means preparing your return in full and letting you know exactly what you owe (or better yet, how large your refund will be).
We do this because we know that estimates may be wrong (that's why they’re called estimates). And we refuse to take the chance that a piece of information we give to our client (and that they’ll use to make important financial decisions) could turn out to be wrong or misleading.