But, by the time she's moved in, you're already so emotionally involved in the relationship, it's probably going to be difficult to be that rational.

That got tedious and really convoluted particularly if you have a grace period and you have to ration do you retro calculate back over the grace period as days late or not...it led to unnecessary tenant arguments.I now charge a flat $50, no grace period, and I have a similar fee ($35) for any NSF payments (I specifically note in the agreement that a NSF payment will undoubtedly create a late fee so it is clear it's VERY COSTLY to write me a bad check).I make one caveat with my tenants; if they mail the rent to me, as long as it is postmarked before the 1st day of the month, even if it arrives late, I will not charge them a late fee.I have collected one late fee on five properties since I have implemented that policy, and I'm much happier to have my calculated rent on time for my bills than to make an "extra" $15-50 every so often because my tenants can't get it together.

Ah, rational and logical things that we would love to be able to do (change the locks), that would, alas, land us in court on the bad side of the courts here in CA,  land of the Free(loaders) and of the Bra(zen professional tenants).... .

It is easily and obviously fair and reasonable to a rational person.  

Those people will be renting until the local economy picks back up.It's hard to rationalize rents going down when you're going to have an increase in demand.  

Credit utilization is a ration of how much credit you have available to how much is being used.

They always have rational suggestions.  

Rationalization is the most expensive word in the REI vocabulary.

I've said it before, and I'll say it again, "Rationalization is the most expensive word in a REI vocabulary".

It's not a reasonable or rational thing to have an "opt-in" program for landlords, call the voucher for the tenants "income", and then not allow landlords to discriminate against the source of tenant income.