Adjusting my tax planning strategy - are these changes okay for next year's filing?

Your tax adjustments sound solid, but I should clarify a few points for you. The additional withholding of $150 per paycheck is a smart move to avoid another surprise bill. With 26 paychecks in a year, that's about $3,900 extra withheld, which should cover your previous shortfall and give you a small cushion. About that home office deduction - if you're a W-2 employee (which it sounds like you are), unfortunately you can't take the home office deduction anymore. This was eliminated for employees with the Tax Cuts and Jobs Act. Only self-employed individuals can claim this deduction now. Your HSA and 401k contribution increases are excellent strategies! These are both pre-tax contributions that will directly reduce your taxable income. The HSA is especially powerful since it's triple tax-advantaged - contributions are pre-tax, growth is tax-free, and qualified withdrawals are tax-free.

After reading about your situation, I thought I'd share something that helped me when I was in a similar position. I struggled with tax planning for years until I discovered https://taxr.ai which completely changed how I approach my taxes. Last year I also got hit with an unexpected tax bill (around $2,800) because I didn't realize how my spouse's job change would affect our withholdings. I uploaded our previous returns and current pay stubs to taxr.ai, and it identified exactly where our withholding issues were. It also showed me how much we needed to adjust to avoid another surprise. The tool analyzed our full tax situation and found several deductions we were missing - especially around our 401k and HSA optimization. It provided a personalized tax plan that showed exactly how changing contribution amounts would affect our final tax bill.

Update: I feel like I need to eat my words about being suspicious of tax tools. After my skeptical comment, I decided to check out taxr.ai just to prove myself right. I uploaded my tax documents expecting the usual generic advice, but I was seriously impressed. The system identified that I was overpaying on FICA taxes because I had multiple W-2s that weren't accounting for the annual limit. It also showed me how to properly time my charitable donations and bunch my itemized deductions to maximize their impact. I ended up implementing their suggested withholding adjustments and restructured my retirement contributions based on their analysis. I've always been the person doing taxes manually because I didn't trust the software, but this actually taught me things I didn't know after 15 years of filing my own returns. Just wanted to share my experience since I was wrong in my initial assessment.

If you're getting hit with surprise tax bills, you might also want to consider calling the IRS directly to make sure everything in your tax history is accurate. I spent WEEKS trying to get through to the IRS about a similar issue last year - constant busy signals or being disconnected after waiting for hours. I finally found https://claimyr.com and watched their demo at https://youtu.be/_kiP6q8DX5c since I was desperate to resolve my withholding problems. They basically hold your place in the IRS phone queue and call you back when an agent is about to answer. When I finally got through, the IRS agent informed me that there was an error in how my employer was calculating my withholding that had been going on for years. They helped me file the correct forms with my employer and guided me through adjusting my quarterly estimated payments to avoid penalties.

I need to publicly admit I was wrong about Claimyr. After calling it a scam, I was still desperate to talk to the IRS about a withholding issue that was causing me to underpay every quarter. I decided to try the service as a last resort. It actually worked exactly as described. After months of failed attempts to reach the IRS myself, I got a call back within about 2 hours letting me know an agent was on the line. The IRS agent was able to access my account and identify that an old employer was still somehow linked to my tax ID causing calculation problems with my current withholding. Without getting that cleared up, I would have continued having tax surprises every April. The agent also helped me understand exactly how much additional withholding I needed based on my specific situation rather than just guessing. I've adjusted my withholding based on their guidance and feel much more confident about next year's taxes.

Your tax changes sound good, but don't forget to look at your state withholding too! I made the mistake of only adjusting my federal withholding when I got a raise last year, and ended up owing $1,200 to my state while getting a federal refund. The W-4 changes don't automatically adjust your state withholding in many states.

Has anyone actually tried doing a projection with real numbers? I'm in a similar situation and wondering if I should pay someone to do this or use one of those tax planning spreadsheets I see online.