@Kelly Cochran Airbnb is definitely one of the safest when it comes to hosting any length of stay. I just ended a 9-month stay through Airbnb and faced very minimal issues. They were very polite, clean, and after the first two weeks, they didn't ask me a single question and were very self-sufficient. I couldn't have asked for a better LTR, but this also depends on the guest. Earlier in the year, I accepted a 3-month stay that developed into moving into a new unit on-site for an additional 5 months. After the first 3-month stay, my cleaners walked into a horror show. All of the furniture was destroyed with burn marks, stains, damage from a dog they acquired after they checked in, urine stains, holes in the wall, etc. I fought with Airbnb and the guest for over a month trying to get something back for the damage as the entire unit had to be repurchased, repainted, renovated. Airbnb also prohibited me from ending the current 5-month stay without absurd penalties like a full refund, no superhost for the year, a large cancellation fee, and the cost of rehoming him for the remainder of the stay. All I could do from that point on was wait.
I lucked out by just happening to run into a family member visiting who footed the bill for both stays. I presented the documented damage and the family member paid for the damages of both units once the second stay was over. The moral of the story, even after a few horror stories myself, I still wouldn't issue a full credit/background check for MT/LT stays. I do require all guests, regardless of the length of stay, to sign a rental agreement set up through my PMS system, and I HIGHLY recommend you do this. A lot of guests will be deterred by having to sign a binding lease, but the rental agreement does the same thing and is just a little less scary to guests. Since establishing a rental agreement, I have won almost all of my cases with Airbnb and guests.
I think you should have some sort of screening process, however. I use SuperHog for every guest as well. This just ensures you're not homing a sex offender in an area they should not be in.
As for cleaning, I've hosted a good number of MT/LT stays and can honestly say you should require a monthly touch-up clean when pets are involved. I had a 4-month guest that came with 2 cats and a dog as they were in the process of renovating their home. I required a $50 touch-up cleaning each month and they seemed to have no problem with it and actually enjoyed the cleaner space. My cleaners didn't do anything extra; just the important "please don't destroy these items" maintenance cleans, i.e., scrubbing appliances, checking furniture for pet damages, floors, dusting, rugs, and bathrooms. They didn't do linens, they didn't do dishes, and they didn't replenish any amenities. They tidied up and made it look nice while checking for damages and maintaining the items that most people miss in their own homes.
The last piece of advice: make it VERY apparent what you will be supplying to them in terms of amenities. Some guests will book for 3+ months and expect to never run out of toilet paper, shampoo, paper towels, or ever have to wash towels and linens. Good luck to you!