It's not like you can just raise the joists a foot and secure them to the 2nd story walls.

It takes less than 2 weeks to find a qualified tenant and process them through a rigorous tenant screening process.Even in situations where there will be some re-painting and some renovations, the tenants are just happy to find a secure, good apt in a safe and trendy neighborhood.When I build my Business Plans, Vacancy cost is projected to be ZERO in my investment localities.If a friend or relative invests in a different location, then I look at the asking rent versus the Fair Market Rent (FMR).If the asking Rent is approximately the same as the FMR, then, depending on the vacancy rate of the target area, I would estimate 1 month vacancy allowance.IF the asking Rent is significantly below the FMR in a highly dense locality, then there is no point on adding a vacancy of any significant value.I once had an apt with a FMR of $3k per month.

Here's a good start: NY Tenant RightsYou should know the law and review it regularly to keep up with changes, particularly in a liberal state like NY that is regularly changing.

@Tony Castronovo If they are the ones I am thinking of they are not very secure. 

If this is your primary home, then maybe there's a reason to over pay...school zone, job, security, etc. 

I have traditionally offered good security at a 75% LTV and 15% interest with no points but at this point, I am starting to get more flexible.

A bad tenant can cause you $100,000+ of damage and no amount of security deposit can save you from that.

Now that they live in it, they have regular renters begging them to go on vacation for a week so they can come stay in it. 

I would love to touch base with you down the road and see if you were able to secure that rent easily.

Think of all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.