How to allocate for vacancy with tenant in house?

[Samuel Mallery]

If I'm looking at a house with a voucher tenant who has the state paying 100% of the rent and the tenant is looking to resign, how much do I allocate for vacancy? Still go with 8% to be conservative or can I drop this to 5%.

In the long run I figured there will be vacancy at some point but wondered about what to allocate when running numbers on it now

Thanks!