I find it interesting that nobody really crunches the actuall numbers in Real Estate which I think is part of the cognitive dissonence we practice in order to make our investments look a little better.No 1031:Purchase: 120k, Sold 330k = 210k in just equityGross Rent: 220k - 60k expenses - 15k taxes = 145k <-- actual rental income$210k (equity) + 145k (rent) = 355k i.e. 355k -30k(closing) -50k(taxes) -25k(renovation) -14,500(recapture) = $245k=245k profit (including all rental income, tax deductions and appreciation.So if you had a mortgage, you would subtract the 145k in rental income and add 30k in principal.

This loan type looks at the rent currently generated by the property OR the anticipated market rents (determined by the appraiser) and compares it to the monthly principal, interest, taxes, insurance and HOA (if applicable).

You will then have a few options with that rent money....you can put it into principal or you can start saving it to purchase yet another property.

Look at your monthly payment (PITI = Principal,Interest, Taxes, Insurance) + HOA + (other maintenance fees if any) and if this amount is less than what you charge for rent (whether its Long, Mid, or Short Term rentals) and you are happy with the positive cash flow, then yes.Or maybe you're breaking even with the condo but you have  knowledge that the condo will explode in value due to some business/attraction/law/policy that will prop-up the sales price in the near future, then yes.Really, it boils down to what your goals are for this first investment.

should i start adding extra to the principal immediately or keep paying the usual?

The current draw back is it doesn't cashflow as well as it could... mostly due to complicated longterm tenants.

You will then have a few options with that rent money....you can put it into principal or you can start saving it to purchase yet another property.

When I am done with school, we will refinance the mortgage, pull out all of my joint ventures principal payment plus an additional 10-15 percent for them to keep as a term of the deal.

Forced appreciation, appreciation, tax savings, principal paydown and (the most valuable in my opinion) experience. 

Here's a casein FL - Seller in foreclosure has 120k principal @4%, Shes 10k in arrears, house is worth about 250k, good condition.She wants to stay at the house, but doesn't mind selling it if needed.She will likely not qualify for a loan mod at the moment, good amount of equity.She works in the medical field, just took sick and fell behind.I was thinking of offering to pay her 10K in arrears and creating a 2nd mortgage @ 10% interest.if she defaults, i can foreclose,  as there is a bunch of equity there.any thoughts of a better scenario that i can make more of this situtation?