PSA to make an account at the IRS website and continuously monitor your previous tax years. Almost done resolving an issue that came up this year but boy has it been a PITA. The IRS adjusted my AGI for a tax year from 6 years ago then claimed I owed. They mailed a CP2000 notice to the wrong address but otherwise attempted no communication and this issue sat festering for another two years. Last month I got a CP40 notice and starting getting hounded by the private collections company they gave my "debt" to.

After hours on the phone with the IRS, we determined the error was on their end, but the process to resolve this has been cumbersome to put it lightly. I've had to dispute with the private debt collector and start a paper trail in case this hits my credit.

I did learn though that if you move around a lot, different departments within the IRS use different systems and those systems may not have up to date information. For example the department that sends out those CP2000 notices was about 2 years behind from my current address.