Below is a Quora question I once answered with the title of this post being the question asked. The answer below is unedited and just as answered
Separate family money/finances from business. There is so much uncertainty. You have no clue if the venture will succeed. There is so much risk and uncertainty. You don’t want to take family finances which are the product of years of hard work and sweat and blow through it in a few months. Things like that have the ability to break apart families and cause feuds. Instead focus on trying to bootstrap and even try to see if the problems you are trying to solve exist in the first place. Chances are if the problem you think exist does exist, you should be able to bring in some revenue on very little and have a massive ROI.