Depreciation has nothing to do with being an RE Pro.
Depreciation starts on the date the property is placed "in service". This is generally the day you put the FOR RENT sign in the front yard. It's the first day a renter "could" have actually moved in. Depreciation is required by law. Your nor I have any say in it.
Keep in mind also that depreciation is not a permanent deduction. At some point in time (usually when you sell the property) all prior depreciation taken on the property is recaptured and taxed in the year of the sale. Again, we don't have a say in this, as it's the law.
For property improvements, you don't even enter them into your tax return until the tax year they are actually placed "in service". So for example, say you put a new roof on the property in 2017and paid for it in that same year. But because of other ongoing renovations the property remained vacant until 2018 when the other improvements were completed. So "that roof" was not in service at all in 2017 and would not be entered at all on your 2017 tax return. You'd enter it on the 2018 tax return included with all the other property improvements you did.
