Modern well-constructed condos will probably last a long time.

The main issue is that to do the ADU you have to spend so much bringing other items up to code like electrical, plumbing, lighting (windows) and egress.

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.  

Another struggle i have with STR is replacing small items continually which ties back to pricing.

Wind is one of the subtle items that Insurance companies are starting to exclude. 

The best place to start is with a spreadsheet that has every every cost itemized. 

We have 8 business entities availing of their services, and as "advisors", they should make business life easier -- not add more work on your plate --- but instead, my team and I have been checking for mistakes, or following up on action items, missed deadlines, and paying penalties to the IRS and Secretaries of State due to their negligence.

The poster was asking about broken/damaged household items and guests destroying a rental. 

The biggest problem I see is that most of those items should have been itemized from the tenant deposit.

Gifting equity in a house may be more trouble than it is worth if you are not near the life-time exclusion1) Potentially having to get the property appraised everytime an equity is gifted2) Having a title company update the title every time3) Exemption of the gift tax return is normally for cash gifts below the annual gift tax exclusion, you may still need to file if you gift non-cash4) If there is partial ownership over several years, having to properly pro-rate certain items such as real estate taxes, mortgage interest and rental income if the property is a rentalBest of luck