I just finished updating my spreadsheet for the new year, which means copying all the new tax figures (tax brackets, contribution limits, etc), and I'm excited to see how close I was with my tax planning. I'm unfortunately expecting a sizeable refund this year because my employer did a weird overcorrection when I sent in an updated W-4, and I just gave up. I paid a fee last year because my bonus was significantly lower than expected, which really sucks because I only have 1-2 paychecks to fix my withholding since my bonus hits in Dec.
Anyway, I'm going to try fixing it yet again, so we'll see if I can dial it in a bit this year.