One of the most important decisions you need to make is when to actually begin approaching investors.
Each start-up is different, but nearly every start-up should be bootstrapped for as long as possible; there is no point in giving outside investors equity, paying for admin and legal fees, and spending time (that could be spent working on your product) just for the sake of fundraising. If you can get your company to profitability without raising money from outside investors, you should.
The decision on when to fundraise also depends on the founders’ connections and experience in the start-up industry. If you have exited several companies in the past and have connections to investors, then the timing of the fundraising process will be different than for someone who is a first-time founder.
Most, however, are not experienced entrepreneurs, and do not have the ability to bootstrap the company indefinitely. That means they will need to seek investors sooner or later. The good news is you can raise money fairly early on in a start-up’s journey. As long as you have a strong idea, and do some work around putting together a pitch deck that explains how this idea will become a viable business, you may be able to approach (relatively small) investors. It typically takes three to six months to raise funding from investors; sometimes, a lot less or a lot longer. Depending on how much money you have in the coffers, you will probably need to start looking for capital at least six to nine months before you find yourself strapped for cash.
One thing to keep in mind is that it is better to aim low and raise more than you had planned, than aim high and lose face when you do not quite meet your goal. Ideally, you will only need to raise funding just once from outside investors before you reach profitability; however, this is rare. More realistically, you are likely to raise money for the next one to two years, and will need to fundraise again after that.