We have a large estate tax balance that an Offer in Compromise has been submitted on. We are likely to have it rejected. The very poor accountant we had previously missed the Tax Court deadline to challenge the amount, so we don't have that option. We are 18 months away from the 10 year anniversary of the relative's death. I am contemplating every option, including letting the clock run out. I know that an OIC, and appeals, cause the clock to stop during those periods. But is 10 years the cut-off for the IRS no matter what, or can they still pursue collections after it?