She also issued a multi-page memo when form 3115 (repairs vs capital expenditures) came into effect explaining the ramifications to real estate investors, and whether and how they should file the form (All this was included because you were her client, and she files the form for you.) 

Major expenses that are often overlooked are capital expenditure repairs, roofs, hot water heaters, HVAC etc. 

He discusses capital expenditures, turnkey properties, cashflow, and why he thinks that $40,000 properties won't cashflow.

What is my reservesamount that I need in case of unexpected capital expenditures?

The rent needs to cover the mortgage, vacancy, insurance, property taxes, repairs, maintenance, property management, capital expenditures, and any other expenses that are applicable (utilities, snow removal, landscaping).

How can these cost-estimation principles be leveraged to create a more robust financial model for long-term rental property investments, considering factors like ongoing maintenance, capital expenditures, and market fluctuations over time?

What have you set aside for reserves and capital expenditures and for such things as legal fees, etc.?

.)• 5% for Repairs & Maint; (Repairs happen even on new builds)• 5% for CapEx; (Larger Expenditures will happen over time, so you have to figure for them.)• ?

What is my reserves amount that I need in case of unexpected capital expenditures? 

Time expenditure and cost as not really a factor for me but like was mentioned by others, is there any real value in focusing on this?