Under IRC Section 6502, the IRS has 10 years from assessment to collect. After the CSED passes, the debt goes to zero. This is one of the most powerful provisions in the tax code.
Certain actions toll the clock. OICs toll while pending plus 30 days. CDP hearings toll during the entire pendency. Bankruptcy tolls plus six months. Strategy matters: filing an OIC with 18 months left on the CSED is often worse than waiting in CNC. We calculate CSEDs and build strategies around them.