Estimating expenses post-purchase

[Sushil Iyer]

When analyzing a deal, the expenses data available (opex, vacancy, PM, capex, etc.) is at the time of purchase. However, this data is bound to change post purchase. What are some tips to estimate what these expenses will be 6M, 1yr, 3yrs post purchase? Alternatively, are there some ballpark estimates for each expense item (e.g., 8% for vacancy, 3% for capex, etc.) that can be factored in as realistic or worst case scenarios when analyzing the deal? Thank you.