Comment Re:And they've already stopped (Score 1) 632
There are all sorts of reasons why someone might not know far in advance, and if they don't want to micromanage their W-4 they'll end up with a refund at the end of the year.
Using myself as a case study, I'm at the point in my life where a lot of things are changing from year-to-year, and it's not always obvious at the start how things will go. For example, I bought a house this last year, but I didn't know precisely what my budget was going to be for the house at the start of the year, since it depended on a few other things. The year before that, I had a relative die and I donated a sizable chunk of the inheritance to charity, which ended up being a rather nice deduction. I switched to an HSA last year. I began investing a few years ago. I expect I'll be married and have kids within a few more years.
Maybe once things stabilize a bit you shouldn't have an excuse, but I'd rather not go through tax documents multiple times a year to calculate my deduction and adjust my withholding. I have better things to spend my time on. I'd rather just set something reasonable and have an expectation that I'll get back a modest refund whenever I do my taxes at the end of the tax year.