Property emergency fund question

[Luke Woods]

how do you calculate how money money you should have in an emergency fund for the property to cover vacancies/repairs? I will give you a scenario. Lets say the home you own and rent out is valued at 125k and was build in the early 80's but is in good repair and the roof is fairly new. Would 5k be enough to where you wouldn't have to worry? Obviously if the fund is emptied for a repair you would replenish it but how so you all figure the correct amount of "just in case" money