Credit Score Requirement

[Jordan Rajchel]

I am working on getting my first rental property rented out. 

I read Brandon's "The Book on Managing Rental Properties" and am requiring at least a 600 credit score. My question is, do you typically require that every person on the least have a 600 credit score?

I am also requiring income 3 times the rent which is 3600 per month. 

One woman responded that they had the income covered between, her, her husband and her son who lives with them. Was just curious, since I will need all 3 of them on the lease, shoudl I also require that all 3 meet the credit score requirement?