Hi womble66, try a guesstimate first.
Eg construction cost [in the 80s, it's around $50K] now it's around $150K
other items eg curtains/carpets = big depreciation items around 10-20% pa.
light fixtures are also worth depreciating
Items under $1000 in costs + installation can go into the Low Value pool where it can be written down very quickly eg 37.5% [pls check this]
So if you have a total of $5000 to depreciate, & your tax is 30% then you get back $1500
The $600 you pay for someone to do the schedule is also tax deductible so you pay $420
You'll end up with $1080 and the schedule is used for the rest of the term you continue to own the property.
With new builds, you can use the building costs & there's no need to get someone to do it for you.
For a very old house with no built in furniture, I just estimated the 2nd hand cost of wardrobes etc [HWS usually around $950] & my accountant accepted it.
Hope this explanation helps you.
KY