How long does it really take to make a comic book?

A quick beginners-style overview to how long it takes to make a comic book... based on industry averages from the large publishers. Absolutely there are exception to this... smaller companies, indie creations and crowdfunding absolutely behaves differently at times. But as a starting point and general rule-of-thumb, this is a great way of understanding the timeline of concept, budget and creative team selection to in the hands of customers.