I would invite you, to decide what areas, of REI, you want to focus upon that fit your skill sets, personal attributes, and Investment Objectives.

Each one of those areas have different attributes to maximize potential.

The portion OF the gain that is attributable to depreciation is actually taxed at his ordinary incoem tax rate for the year (at a max of 25%) Example: Live in home 2 years Rent home for 3 years - Took $10k depreciation over those 3 yearsSell home for $100k gain $90,000 = $0 tax, primary residence exclsuion$10,000= taxed at ordinary tax rates, up to 25% 

Here are my initial pro/cons of each approach:DIY RehabPro's: Gain rehabbing experience, ability to better understand timeframe and costs of typical rehabs, save $$ on labor costsCon's: Longer rehab timeframe and increased holding costs, quality of work may not be as high as a professional contractor (or perhaps the opposite because I have a higher vested interest, it could be argued either way)Contract it OutPro's: Ability to try out contractors to form relationships to support future flips, shorter time frame/holding costsCon's: Higher rehab costs attributed to labor , less personal rehabbing knowledge and experience to support decision making on future flips.

There are many here on BP that have been in this business 10, 15 or 30 years and I doubt any of us will attribute our success to cutting commissions.  

No, I use a HELOC for my DP.However if you do not base your calculations using a hypothetical 100% financing (regardless of your DP) you are not attributing any value to your dead equity.

If debt-financed real estate is acquired via an IRA, any income attributable to such investment will generally be subject to unrelated debt finance income tax.5.

In the case of the water bill, you would count the 1/2 they reimburse you as income and the amount of the expense you paid attributed to your tenant as an expense. 

Among many wonderful hard working, diligent, and intelligent attributes that makes any successful professional - I think the quality I find most common is that they're creative people.

I attribute the rest of the cost to my lack of understanding on the general costs to build.