Count roughly three months from the first time an investor takes you seriously to the day the money arrives. That figure comes from the largest survey of venture investors ever run, and it describes the deals that actually closed. The ones that fell apart on the way took their share of your calendar too, and gave nothing back.
Most of those three months are spent inside the fund, not with you: well over a hundred hours of checking your numbers, calling your customers and speaking to about ten people who know you. You cannot make an investor work faster. You can stop slowing them down. Reply the same day, keep the data room complete before it is requested, and run several conversations at once so the clock runs once instead of five times.
Figures from a survey of 885 venture investors at 681 firms by Gompers, Gornall, Kaplan and Strebulaev, published in the Journal of Financial Economics.