I always recommend having 12 months living costs, less is you already have some established income
1. This means that you will only take on good quality clients and not be tempted to discount or take unsuitable work just to get somebody signed up.
2. You will feel better if you aren’t trying to bootstrap in the business and at home too.
3. Allow a couple of years to get back to where you were financially but there’s a huge variation deoending on the nature of the business and clients, how much time you put in, how much money you invest in automations etc.