If the rent is still paid to you on time and the place is kept in decent order, it shouldn't be too much of a worry for you.However, with the dog, you should enforce a pet fee.

@Charlie Moore only if your lease is legally enforceable

Creating and enforcing house rules as well as policies of what you'll do when guests have conflicts would be important. 

So long as people want to buy things without other people learning about it -- guns, drugs, prostitutes, trips to a pub that were supposed to be to the office -- there is going to be a market for some sort of untraceable medium of exchange.So long as all digital finance leaves a computer trail that can be easily followed by law enforcement and divorce attorneys, people are going to have a use for cash.People may want to soak silver coins in Clorox or just take their chances, but trust me, there will always be some kind of cash.

They only do that for law enforcement, judiciary and victims etc.

that used to be Portland Oregon.. but the lack of leadership and allowing the BLM riots  antifa riots for 6 or 7 months straight plus homeless Drug and no enforcement of crime under 1k has caused the hipsters to flee to the bergs and the business's to do the same they simply killed the urban core.

If you want leverage, you'll probably need to review the leases, look for violations (people living there who aren't listed, pets, etc) and then go to them with the pitch that you'll update the lease so they can keep doing what they want to do, but it's at market rate, or you'll enforce the lease as drawn up, and they'll be looking at a $77 increase.Another option is cash for keys.Another option would be that you can serve a no-fault eviction if you need to do repairs/renovations (look up SB 608 and make sure it applies).

I saved it from being foreclosed on, paid back owed mortgage $28k, city code enforcement fines $$, I assumed the mortgage at 3.125%, cleaned the entire property, and fully rehabbed it.

Let's face it - the seller selected the tenants and if you buy the property with the existing tenants, you're stuck on doing anything until lease end as the tenants have an enforceable lease.

City enforcement is cracking down on permit issues but we still pull permits for all our renovations.