More work, more time but you can take advantage of a nice cost segregation / bonus depreciationThis is the truth! 

I received a quote in Southern California, but it requires year-round accounting at over $6,000 per year.Would a general tax professional be sufficient, or would I risk missing out on significant savings?

Non-passive to achieve this level of return.Add the addition of the ADU makes the main unit rent controlled if over 15 years old.the work to add an ADU likely exceeds the effort of a brrrr that can achieve infinite return  Experienced investors are adding multiple ADUs by leveraging items like bonus density, committing units to affordable housing, etc.  

I live locally in round rock!

But it also means you have virtually zero bargaining power as the seller can reuse any and all repairs and just keep your 6 months of rent as a bonus. 

Turning a "SFR 3bed / 2bath with a bonus room" , into a 4 bed / 2 bath with the simple addition of a closet, is one of my favorite value add plays. 

Interest always paid on time, and principal was returned with bonus right on schedule.

., structural updates) can be added to your basis, while maintenance costs are deductible in the year paid.Since bonus depreciation is now at 40% for 2025 and 20% for 2026 under the current law, future real estate investments will have fewer upfront depreciation benefits.

A good real estate accountant can save them thousands of dollars by leveraging entity selection and formation, tax deductions, cost segregations, bonus depreciation and tax planning.I recommend that they find a tax accountant who specializes in real estate taxation, business taxation, financial planning and tax planning.I would also recommend that they look for a accountant willing to work with them throughout the year, who can help them strategize and who is responsive when they want to know the consequences of the financial decisions they are making throughout the year.Good luck.

STR is just a bonus.