Generally speaking, with SFR or small multis, I just rely on the lease/rent roll (and some form of proof of payment; i.e. bank statements, deposit receipts, tax returns, etc.). 

Quote from @Phillip Austin: There are two alternatives to a security deposit, which I speak about in my book.

You can't charge extra pet rent or even a pet deposit because it's legally not considered a pet.

Key points include:Security Deposits: In Indiana, there’s no legal cap on security deposits, but you must return the deposit (minus any valid deductions) within 45 days of the tenant vacating the property.Evictions: Follow the formal process carefully.

We also received a $2400 security deposit.

Hey @Thanh Lu, we don't do much direct bookings but we do have a $500 security deposit.

WOW.. 40k plus deposits on a home to be built.. ??? 

I have a separate interest bearing account for security deposits as required by my state laws.

I view it as a tool in a toolbox to help you "trim the fat" off the bottom of your portfolio, so you can keep growing with new acquisitions. 

You’re not using a PM, AND you’re assuming you can charge a service animal a deposit and pet rent?