One of the most frequently stated truisms in personal finance is that Americans aren't saving as much as they used to.

As of April 2018, the personal savings rate stood at 2.8%—a far cry from the historical average of 8.2%. While this isn't quite as dire as it sounds, it does bring up the question of how much households should be saving today.

How Much Are You Supposed to Save?

There are several rules of thumb for saving, but the most popular suggests keeping enough to cover at least six months’ worth of expenses. This method correctly identifies the purpose of a savings balance, which is to protect your finances during periods of unemployment or unexpected emergencies. But according to government data, most people fall short of this suggested baseline.

In the Federal Reserve's most recent Survey of Consumer Finances, households reported a median bank balance of $4,500. In the same year, the Bureau of Labor Statistics calculated that U.S. households spent a monthly average of $4,776. While median spending is likely lower than that, it's clear most households don't have bank balances anywhere close to covering six months' worth of expenses.

It never hurts to aim high when saving, but comparing your own savings to such a lofty number can be discouraging and counterproductive. Another common principle for growing your savings recommends dividing your monthly income in a fixed ratio: 50% goes to household expenses, 20% is saved and 30% is left for personal spending.

When it comes to motivating yourself to save, the 50-20-30 rule may be more effective simply because it's easier to begin than the six-month principle. Of course, saving 20% of your income each month will help you save up six months' worth of reserves far more quickly. The two methods go hand in hand. However, they do represent different modes of thinking about your savings: one is a goal, and the other is a method for reaching that goal.

Why Are People Saving Less?

It's proven difficult for experts to agree on why Americans are saving less over time. Some blame rising costs of living, while others suggest that better access to credit means that more people can make large purchases without having to save for long periods.

In addition, the financial shock that many households experienced in the recession a decade earlier may have left some consumers permanently mistrustful of banks. Others may be unwilling to go through the trouble of setting up automatic savings transfers that drain their checking accounts, exposing them to bounced checks and overdraft penalties.

The recent interest rate trend for deposit accounts also plays a part. Standard savings accounts at most major banks earn 0.01% APY, or a penny for every $100 per year. This leaves consumers with little incentive to keep money in the bank. For households that invest their assets, the strong performance of the stock market offers a stronger rate of return.

Are Savings Accounts Worth the Bother?

Despite these low rates, there is good reason to have a savings account that's separate from your investment portfolio. As the six-month rule implies, the main point of a savings balance is to help you weather temporary loss of income or spikes in personal expenses—not to maximize growth. Beyond reducing your financial risk, saving for the future can expand your options when it comes to reaching large-scale life goals such as buying a home.

It's also possible to obtain a much higher savings rate if you're willing to consider an online savings account. Many nontraditional players have begun offering deposit account services through the Internet, with fewer fees and better interest rate offers than traditional brick-and-mortar institutions. Online savings rates currently average between 1% and 2% depending on the bank.

Ultimately, a savings account needs to be secure and easily accessible. That means you should make sure that your online savings bank offers both FDIC insurance and a quick way to access the funds via mobile app or online transfer. The offer of a high interest rate is a welcome bonus, but you should never prioritize rate over these basic considerations.

Maxime Rieman is Product Manager at ValuePenguin. Educating and assisting shoppers about financial products has been Rieman's focus, which led her to joining ValuePenguin, a consumer research and advice company based in New York. Previously, she was product marketing director at CoverWallet and launched the personal insurance team at NerdWallet.