Proration of investment income / depreciation in owner-occupied SFH w/ tenants

[Justin H.]

I'm looking for a good resource to help me with a tax question. I recently purchased a 3br SFH for 75k and am improving it with another 60k (135k all-in), and I estimate it will appraise at $170k once completed (will cash-out refi on back end, I've financed purchase/improvements w/ private loan). I intend to live in one of the bedrooms and rent out the other two. I will have rental income from two tenants (friends), but this will also be my primary residence. I want to make sure I am handling the taxes properly from the outset, as once I refinance later this year I want to make sure my calculation methodology for claiming expenses/depreciation/etc is consistent for as long as I hold the home. So my questions are:

1. If I live in one bedroom, can I depreciate 2/3 the allowable depreciable value of the home each year?  Do I need to measure square footage?

2. For utilities, mortgage payments, maintenance, etc. do these expenses need to be prorated for write-off or can I deduct the full amounts?

3. If I later move out of the house altogether, can I then begin to depreciate the full amount in the year that I move?  Does that particular year need to be prorated based on days lived in the residence (assuming yes) ?

4. If I later decide to not have roommates and the home becomes my full primary residence, how is this handled from a tax standpoint? Do I essentially "freeze" the depreciation (don't claim any more going forward) and discontinue deduction of maintenance/utility expenses as of the effective date of being a loner?

Basically, I am going to have roommates paying me rent in a house that I own and I want to make sure that it's handled properly WRT taxes but don't want to make mountains out of molehills.  It seems like this would be a pretty common situation but it's difficult to find good resources out there for advice.  Any input would be much appreciated.  It may be as simple as pointing me to another blog post or forum thread....