Do you wait until profitable or can you start early stage?
I see two questions. What way and at what time. I can answer the timing question: Try to get as far as possible without investors. This way you have to give away less % of your company.
There are however 2 things I want to point out:
1. Don't forget that you need to start looking for investors before you actually need the money. I'd say start fundraising 12 months before you actually need the money.
2. There are many businesses where you'll need a lot of money from day 1 because speed to market and speed of growth matters a lot. Some people would probably say that every startup could grow faster with more money.
Its all depend on presenting your idea.
Instead of saying your idea.
it's always better to do the market research to know the demand for that business.
Make a prototype and apply on a small number of people to know the worth.
In that validating process, before you present the idea to the investor, first you will get the idea, whether your idea has demanded or not.
So when you meet an investor, you can show the cash flow and demand of the business which is proved already.
In this way, you will get an investment easily.