Every year, I am a little astonished that “tax time” for most people is February, March, or April.
With an exception of a few things like IRAs… December 31st is the last day you can do things that impact taxes. Its the last day to buy things, transfer things, create entities, buy bonds, sell stocks, transfer accounts, reappraisals, open HSAs, etc.
And for that reason, I take a couple days in December to do my taxes. Sure, I don’t have my final 1099s, 1098s, W2s, and all my other tax forms… but I have enough to have a pretty good idea how things are going to land… and because I know how they are going to land, I don’t have to be a victim when tax time comes around.
Taxes aren’t something that happens to us- they are an outcome of our choices and financial experiences throughout the year- and if you have a clear 
picture of what that is as you wrap up the year, you can make decisions at the end of the year to end up precisely where you want to be.
So while this is a festive time of the year where we often think about spending- its not a bad time to use one of those vacation days to take run your financials and see if there’s any great last minute moves you can make to put you in a better place in February- maybe you got a little more depreciation than you expected, some stocks could use a rebalance, or its a good time to convert some of your IRA to Roth- it may actually give you a good reason to be a little more merry during the traditional tax season!