OBVIOUSLY a unit that has been continuously occupied for at least 15 years, and VISIBLY had issues as described, will most certainly have many other unnoticed or hidden issues due to age that are also best addressed at vacancy.

If they are VERY professional, they will have their processes in writing as verification that policies are enforced equally and fairly by their entire staff.6.

I am in your position/age bracket and live in an expensive area as well.  

Don't rent to people under 25 years of age and require that the renter (25+ year old) be on premises (no parents renting a place for their kids to go party).

What age or year built is too old for you and why?

Tell us more about the property, (type, age, size, price). 

Everything you shared I respect you for it, I wish I had that mentality at that age as I’m sure would would’ve too.

If negatives aren't as much of a factor for you some general criteria for your credit score are credit utilization, on time payments, and age of accounts.

If they are VERY professional, they will have their processes in writing as verification that policies are enforced equally and fairly by their entire staff.6.

You can't control your age.