The kaffara mentioned in Quran verse 5:89 is only for serious oaths. However, one should not take swearing lightly, whether upon God or otherwise. Such behavior leads to hypocrisy in our personality, which gets in the way of tazkiya. We should instead aim to be truthful all the time so that people believe in everything we say without depending upon swears.
Quran 5:89
Translation by Asad
GOD will not take you to task for oaths which you may have uttered without thought, but He will take you to task for oaths which you have sworn in earnest. Thus, the breaking of an oath must be atoned for by feeding ten needy persons with more or less the same food as you are wont to give to your own families, or by clothing them, or by freeing a human being from bondage; and he who has not the wherewithal shall fast for three days [instead]. This shall be the atonement for your oaths whenever you have sworn [and broken them]. But be mindful of your oaths!’ Thus God makes clear unto you His messages, so that you might have cause to be grateful.