As an adult, I still practice this. There are two piggy banks in my house. One is downstairs and one is upstairs. I put all my change in the one downstairs and my husband sometimes contributes to the one upstairs. When it's full or when I've fallen on harder times, I cash them out and take them to the bank. These coins usually go into my down payment fund.
This might only add up to a few dollars, but it's hassle free saving that really adds up over time.
However, be sure that if you do this you count out your change yourself. Banks will happily give you little paper coin rollers. Coinstar machines and other services skim a fee off the top of your money.
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