The phrase "smart thing" refers to something that is clever or intelligent. It can be used to describe a wise decision or action, or even a device or technology that is innovative and advanced. Full definition
Over the past year I've written about doing smart things with money — investing for the long term, saving for retirement and paying down debt. (ourbigfatwallet.com)
There are plenty of smart things to do with $ 10,000. (moneysmart.gov.au)
The young lady has done a very smart thing. (alanrinzler.com)