The half of a percent theory

It goes like this:  a book manuscript of 50,000 words. One percent of that is 500.

So .5% is going to be 250 words. You can write that in an hour or two.  So you need 200 days to accomplish this, assuming you aren't going to be writing more than 3 hours on any day you devote to the project.  In three years you have 1,095 days to write, so you need to be working on actually writing the book about 20% of your days. You should be able to write a book in three years.

This is allowing for the fact that the writing might only happen every 5 days, that some of the time is not writing but research, etc... and that you will get lazy at some point, or simply that ideas take time to develop.

[Update: my pages are about 300+ words in Baskerville 12 point type, double spaced. So I have to write slightly less than a page for the half a percent.