Rental Property Expense Percentages?

[Henry Reimer]

So I am trying to refine my spreadsheet for rental property analysis, and I am trying to figure out what percentages to allocate for the various expenses that come with a property. Right now I set aside 24% of the gross rents for repairs, vacancy, and capital expenditures (8% for each one), and I have not been allocating for property management because I would start out by managing my own properties. I have recently decided that it would be a good idea to plan to have to pay for property management at some point so I wanted to put that in at 10% of gross rents. 

This is where my question comes in, if I were to add up all of those expenses that would come out to roughly 34% of the gross rents (this doesn't even include the financing and utilities allocation). So I was wondering, is this model accurate? What do experienced investors with multiple units have to think about this? Do you guys really spend 34% of your gross rents on repairs, capex, vacancy and property management?

All responses are greatly appreciated, thank you!

[Joe Villeneuve]

Stop trying to use percentages.  They don't apply the same to every property.  You can't guess (that's what you're doing) what the actual costs might be before hand using the same percentages for each property you might come across in the future.

When you come across a property, use the real numbers...with dollar signs in front.  Leave the percentages in the garbage can.