Each account is for a different need. By using separate accounts, you do not run the risk of overspending, nor of cross-spending.
To help illustrate this, we can break down an example of accounts that you would need and use.
The first is a long-term savings account. This is a “retirement-level” account. Or, an account that you will be contributing to for your life, in an effort to ALWAYS have money when you need it, especially during your later years.
The next is a short-term savings account. This account is used for shorter needs. For instance, a good short-term savings account might be a Christmas Club account, or a Vacation Club account, or an Emergency Car Repair account… you get the idea.
The final account type is a daily spending account. We classify this as a checking account. You don’t use a checking account for long-term nor short-term savings. And, to go further, anytime you have more cash in your checking account than necessary, you should think about automatically depositing this into your savings accounts.