Cost Segregation algorithm

[Eric Lin]

Purchased a multifamily, would like to do Bonus Depreciation.

I am stuck at the  Cost Segregation

I see lots of people do 20-30% of house value(without land)

example: purchase price $100k, land $20k, other value $80k.

if we take 30%, would be $24k for Bonus Depreciation.

My question:

1. Can I do Cost Segregation like this by myself like this?

2. Do I need to hire professional for this? what is the most common way to handle Cost Segregation

[TJ Tingley]

My CPA is telling me if i get him estimates of everything on a recent STR purchase i don't need to have a study done. In one of David Greene's most recent podcast Rich Dad's CPA says you absolutely must have one. My investments are smaller- $350k storage facility and $750k STR. Are there firms that will take on smaller studies?