Kant- synthetic knowledge Dotto

How much do we depend on synthetic knowledge? How much can we really rely on and trust our knowledge? If knowledge changes with new observations, does that mean the knowledge we take for granted could be wrong? If all of our knowledge is based on observation done by humans, who are largely imperfect themselves, that leads me to believe we could be living our lives with incorrect facts and misleading truths because the people who found them could have been wrong.