You could easily have someone smoking, bringing pets, throwing parties, etc. in your rental.

Decide how you want to qualify tenants, income 3x rent, credit score above 650, no pets, etc. and then apply those criteria to the current tenants.

And that unit is no smoking no pets.

I just wanted some input on how to best screen tenets, I simply email them some questions and an application (pdf) and ask them to fill it out, most of the time they don't respond ( my though is because they don't have a credit score, they have pets or they have a criminal background)  The application I use is the one from Bigger pockets. 

I agree whole heartedly on the pets.

No Pets" might not be helping.

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.

They inquired about a 3 bedroom in New Britain that I have listed for $1100/month, cold flat - and with a pet, it's $1150. 

It is written into all of our Leases that we will be doing quarterly (sometimes monthly) inspections.Our managers go around with a list to make sure smoke/carbon detectors are working, fire extinguishers are filled and the place is not potentially attracting vermin.We will also make a note of any damage or take pictures of potential Lease violations (smoking in the house, pets, more beds than occupants allowed, etc). 

Today was the last straw when my electrician was in to do some work and reported there is now a cat in the apartment (no pet policy).