At this point you'll need to pay back a fixed percentage of the principal balance (often 1%) each month along with the interest accrued.

They don’t have to default on a principal or interest payment.  

Nope, equity isn't a business expense.Same reason we can only deduct the interest of an investment mortgage payment, not the principal paydown. 

I bring this up as in a lot of cases, people who start with their house hack either go on to house hack another property or move into a longer term living situation like a single family.Just make sure that you're building reserves after you move out of your first house hack deal so that you can keep it for the long run and capitalize on appreciation, principal pay down, tax benefits, and at some point the positive cash flow that grows over time.Here for any other questions you might have!

Mortgage payment (principal, interest, insurance and taxes) is $1,050 and the rent payment is $1900.

But at some point you have to finance the principal, and that is going to dramatically affect your cashflow. 

I am looking for some advice on if I should make extra payments per month specifically towards the principle of my mortgage. I currently own a duplex and live in one side. I used 0% down financing in order to get this...

After paying back the loan principal and commissions, netted proceeds of $3m or a profit of ~$2m.   

The total return value includes the principal paydown included in your payments.A key number that's missing is NOI - net operating income.

I am under the impression that if you are acting as a principal in the transaction, you do not need to disclose you are a realtor.