How do you calculate capex and repairs?

[Spencer Cornelia]

I've begun running numbers on properties and would like someone who has experience to lend a helping hand.  For properties that are basically turnkey, already renovated, and appear to need very little work, I've been allocating 10% of monthly rent to cap ex and 2.5% of rent for simple repairs.

For a property that my partner and I will look to renovate ourselves and will have everything new (basically a gut job), we are allocating 10% of monthly rent TOTAL for cap ex and simple maintenance/repairs.

I know every property is different, but I am curious how you savvy investors on BP calculate cap ex and maintenance/repairs?