One in 5 taxpayers risk a penalty from the IRS for withholding too little in taxes for 2018 — here’s how you avoid it

I try to keep mine adjusted to where I owe $300-$500 at year end. Paid in April. That way I get the most out of my money for the whole year plus. Plus there's no refund to steal. If it looks like I might get some back, I do a Roth conversion. Someday, no tax for me.