For the perpetual “one day” people with some ideas but not sure when to start or how to do it, what would you advise? And what advice would you have out of the gate.
I don't disagree with the this statement at all yet there is more to it than that. You need to ensure that you are mentally and physically in a place where you can go all out for 2-3 years at a minimum. You are comfortable with repeated failures and will not let it stop you from what you are trying to do. You have solid experience in marketing and sales or have someone in your immediate network who is and they can give you guidance or strong helping hand. You are comfortable delegating tasks and working with others and can communicate effectively with your target market. Last but not least I would have my finances in order and ensure that this will not impact the quality of your family's life if you have one.
These are all good qualifiers and positive indicators of more likely success, and that's with only two comments so far.
Good advice on why and how this should be approached may still not give very accurate guidance about when.
I expect more good comments will follow, and the list could get quite extensive.
At some point (maybe even now) it may be impossible for any founder to meet all of these characteristics before launching a particular business, no matter how much time is spent in preparation.
So the real difficult question becomes "when do you start a business if preparations are not ideal and advantages are not largely stacked in your favor?"