A small, monthly habit that takes under two minutes can make a real difference. A simple thyroid self-exam helps with early detection of thyroid nodules and plays a role in thyroid cancer prevention. Thyroid nodules are common, estimates say your chance of having one roughly equals your age as a percent (so a 50-year-old might have about a 50% chance). Most nodules are harmless, but about 3 to 7 percent can be cancerous. Knowing how to check thyroid at home gives you power to notice change early.