What % of rent is a safe estimate for Vacancy/Capex/MGMT/repairs?

[Adam Juodis]

I was wondering, when analyzing a potential property to purchase, what % of rents do you account for to be vacancy, capital expenditures, property management, and repairs? I am starting to practice analyzing deals and running the numbers, but I do not want to lowball my expenses, or overestimate either. I was wondering what others in the community do when it comes to estimating these costs.