Depreciation for a rental property is straight line depreciation where the cost of the rental is divided over 27.5 years to give you an amount you can take for depreciation each year.
The above has a tendency to be misleading. Depreciation is not equally divided over all 27.5 years. The method to use is covered in IRS Publication 946 at https://www.irs.gov/pub/irs-pdf/p946.pdf
For residential rental real estate use the MACRS work sheet on page 36 and Table A-6 on page 70.
Your first year depreciation is based on what month you place the property in service.
Years 2-9 are figured at 3.636% of the cost basis assuming it was classified as a rental the entire year.
Years 10 and up the percentage is different for each year alternating between 3.637% in even years and 3.636% in odd years on the assumption the property is classified 100% business use for every day of the entire year.
Depending on the value of the depreciable property, that .001% difference can matter, even though for most it won't be more than a buck or two difference most likely.
Basically, if you take the property out of service at the end of say, year 6, when you place the property back in service years later, you'll "pick up" with year 7 of being "in service". The program itself doesn't seem to be capable of correctly handling a gap in depreciation without the user manually intervening. (At least, from what I can find.)
