Just to generalize what others have said, ALWAYS buy on actuals, and underwrite the upside on what you KNOW you can achieve.

So far I have never failed to achieve my projected numbers only because I add a conservative fudge factor (virtually all big projects cost more than I think they should but I take this into account on my projections).

What overall goal do you want to achieve by investing? 

Most first time flippers do not achieve a good return for their effort because many times the cost to rehab is less than the value added.We look for a two to one return on our value add costs. 

If you have Excel, you can use a couple formulas to achieve this (note the minus signs)Monthly payments:  =PMT(rate/12, amort years * 12, -principal amount)Balloon amount using the payment above: =-FV(rate/12, ending month of term, -payment amount, starting principal)Say you have a $500k balance, @3.5% for 36 months on a 25 year amortization =PMT(0.035/12, 25*12, -500000) = $2,503.12=-FV(0.035/12, 36, -$2503.12, 500000) = $460,402.95 or ~7.9% of the original balance.  42 months would get you 9.3%

Why not fund everything so you can achieve it all ?

To me equity investments are fine once you've achieved comfortable cash flow, but they won't save you when things go bad like cash flow will...

Hi All,I am currently managing and automating my daily vacation rental tasks through Airtable, which I have connected to a number of online softwares through their API's (Gmail for emails, Twilio for SMS's, Slack for Notifications....etc) in order to achieve my desired custom workflows, and cut down on time spent in front of a computer.I am now at the point of automating my vacation rental bookkeeping tasks and would be grateful for any help with the following:I would like to automatically create a QuickBooks Online Invoice for each customer as soon as they pay for the reservation.

You want to understand all of those things and those options so you can better make the right decision for you and what you're wanting to achieve.

Some quick thoughts on analyzing rental properties in NH (assuming your goal is achieving cash flow, if it is not, then disregard):- If you are putting 25% down, 90% of single-family properties and condos are not going to cash flow any amount that justifies doing the deal and spending your time on it.