First thing to to know when you open a limited company is that you have opened a Business. Businesses do budgeting and planning.
Those who handle their companies as businesses know that a director/shareholder has to declare a salary or dividend after ensuring that the company has enough resources to pay for its expenses and creditors.
For most contractors, the biggest creditor will be HMRC.
If the company is left with no resources to meet its obligations, the director will be charged a tax for borrowing from the company.
You can ask your accountant how much you have to leave in the business, but it is more helpful to approach them with your budget list of expenses and your monthly creditors obligations. Only that way a professional can work viable amounts for you.