Question: How do I know how long a new product will take to document? People are asking me for estimates but the project’s still in a conceptual design stage.

Answer:
Live dangerously and embrace risk by pulling a number out of your ass. If you have at least 5 years experience in tech writing, you should have some kind of gut feeling about it, which is really as good a predictor as anything else.

No matter what you say, people will expect it in a week. Common-sense approaches don’t work in panic situations, so just agree and then make something up. If this feels too much like lying, try to think of it as a marketing pitch instead of a technical document.

If by some bizarre twist of fate, your team still uses common sense, there are several ways to do actual scoping:

• Work backwards from the due date, and figure what you can do in the time allotted.
• Get a walkthrough of the product in person, and use the time to freely discuss the context. Ask questions like “Will it actually look like this to the customer?” Try to summarize the product in one or two sentences as your elevator pitch and product tagline, and then work from there.
• Walkthroughs are also good for seeing actual state of development. If you can’t even get a prototype or working version, that should tell you something.
• Use historical data for similar projects to estimate how long this one will take.

For projects of known types, I would look through my old work logs to see the start and finish dates for comparable projects, by doc type. Major solutions take minimum 2 months to document. New hardware sheets, 1 day to 2 weeks.

Workhours aren’t as important as calendar weeks, since a lot of what holds up a project isn’t the writer. Every project may be unique, but Murphy’s Law generally applies:

“There’s never time to do it right, but there’s always time to do it over.”