For the first few years I plan to flip houses, doing fairly major gutting and updating.  

We got started at 23 with a personal property that we gutted.

Bottom line is, trust your gut and never ever let anyone discourage you from trying anything just because they don't agree with it or are too scared to do it themselves. 

You need to ensure that you're getting the assistance you need to be successful; if you're not, you may find yourself in a bad situation, and even if you get lucky, you may find yourself handing over 50% of your profits for little in return.I would recommend:- Get a list of properties he's owned (and currently owns)- Verify that list- Talk to others he's worked with (other students, real estate agents, contractors, etc)- Ask to see a couple projects he's working on or has completed- Ask about his contractor network and whether you will have access to his contractors- Ask about his material vendors and whether you'll have access to material discountsAnd then make a decision based on your gut...

They pay off quick.My first house was half gutted and a mess, I paid $2,900.00.

Are you wiring a house that's gutted with no sheetrock? 

My first one was a complete gut and the second floor was so bad it had to be completely removed and rebuilt.

We got started through buy our personal property and gutting it.

Here are my major expense lines:AdvertisingAuto/travelCleaning and MaintenanceInsuranceManagementRepairs (minor)Supplies TaxesUtilitiesDepreciation (this is noncash but goes into Sch E)SanitationWater/SewerCapital Reserves (depending on quality of building, I put this at +/- $1,000 per year per unitAs a gut-check, these expenses should be ~50-60% of revenues. 

I instinctively want to pay off the loans quicker, and pay less interest to the banks (15-yr), however I think everyone in favor of the 30 year mortgage is correct; you may pay more over the long run, but you also increase your cash flow which is key to bringing in more properties into your portfolio.