It's good practice to know how much it will cost you to do certain rehab items in your area2.

If you can't pay it off at the end of the month - you don't need to purchase the items with your credit card. 

Once you locate a property you think might be a good acquisition, you need to calculate the cash flow by plugging in actual numbers, like PITI, HOA fees, property management, funds for maintenance and reserves for capex items and vacancies.

Your expense items need to also account for CapEx and property mgmt, even if you will be self managing. 

Now if the tenant wants to sign an early termination form for an agreement to get back so much of the security deposit than that is negotiated.You make sure before such an agreement is signed by both parties that ALL items have been moved out of the unit and that all people on the lease sign the document.

Also, if owner pays any utilities, common area items, lawncare and other related items. 

Gave advice on fixes, offered referrals for contractors, and explained what items were technical fluff vs real issues.

Find NO-Money Down deals, Sell your properties to capture more equity and deploy more to add more units!  

He's got expenses, which isn't broken down by line item.

Teaching a new note investor how to invest in notes is teaching them how to think about notes not what items are on a checklist.