An emergency fund is an account specifically set aside to deal with emergencies such as accidents, medical bills, and loss of a job. It is a way of cushioning one from financial setbacks or borrowing in case of unexpected events and, in some cases, a starting point to solving a problem at hand.

Well, people have different social incomes. Your amount would depend on your income as well as your personal and social situation. It is advisable to use an emergency fund calculator, which will customize your savings based on your income and expenses and level of risk.

 Generally, it is recommended to save at least three to six months' worth of living expenses. It is good to start small and gradually build up the amount. While this is the recommended amount, you can surpass this amount. If money is available, you can have up to 3 emergency accounts; it never hurts to be well prepared.

 While undertaking this process, be realistic about your situation. Consider the state in which you're living, your expenses, and extra responsibilities, i.e., if you're single or living with a family. Learn how to make an effective budget here.

A step-by-step guide to doing this would involve:

• Setting a clear goal: Write down what you are planning to categorize as an emergency and how much you would need for such. It should be attainable to you easily in order to start seamlessly. (e.g., $100 starter fund)

• Open a separate account: determine what type of account is best for saving spending on your expenditure pattern and habits. It has to be separate from your current account or any other accounts for other purposes, such as retirement funds or vacation money.

•  Contribute a fixed amount monthly or per paycheck. The key is to be consistent. It doesn't necessarily have to be per month, but you can have set dates by which you top up your emergency accounts.

•  Use side hustle income or tax refunds to boost savings faster. The more funds you save, the more secure you are.

• Rebuild emergency funds: In the event that an emergency does occur and you use the funds rightfully so, it is in order to refund the account. Set it as a priority and continue filling it up with the means that you previously used to do so. To fill it up faster, you can find means of cutting back extra expenditures to save more.

Emergency funds are for unforeseeable and unavoidable events. Regardless, it is crucial to define your rules around your emergency fund and use it only in real emergencies. 

An example would be using it for medical emergencies that cannot be covered by insurance, job loss, or mitigating consequences of natural disasters, such as homelessness due to a tornado or earthquake.

Mistakes to avoid are as follows:

• Keeping it at home and in cash, it doesn't matter even if you put it in a safe. It is still prone to theft if not from your temptations.

• Using it too often or for minor inconveniences that are solvable through other means.

• Not rebuilding your account after use. Ultimately, it dries up and will not sustain you through your next emergency.

• Mixing your emergency fund with other types of funds. It often comes about when you don't properly define what an emergency is for you.

Recommended accounts are ones that also earn some interest on the side and aren't just sitting idle. This strategy is good because your account grows regardless of whether you decide to boost it with additional funds or not. It is cushioned against inflation and economic changes.

Options include high-yield savings accounts and money market accounts. Lock savings are recommended for people with no self-control around money.