@DavidD66 is confusing safe harbor, SEC179 and the Special Depreciation Allowance. Those are three physically separate and different things.
If this is for rental property, be aware that "residential" rental property does not qualify for the SEC 179 section.
The Special Depreciation Alowance allows you to completely depreciate a rental asset in the first year you place that asset in service. It only makes sense to do that, "IF" you have the taxable rental income to take that SDA against. It is "NOT" common for residential rental real estate to operate at a profit "on paper" at tax filing time. So while you can take the SDA, it more than likely will just get "carried forward" every year and not make any difference to your tax liability.
It "might" make a difference if you qualify to deduction up to $25K of your rental losses against "other" ordinary income. If you "materially participate" in the rental activity, then you "may" qualify for that.
The de-Minimus Safe Harbor allows you to expense certain assets that would otherwise be depreciated, "if" that asset qualifies. One of the many criteria for qualification is that the asset must have a cost basis of less than $2,500. For the other criteria, see https://www.irs.gov/businesses/small-businesses-self-employed/tangible-property-final-regulations and scroll down to get to the safe harbor section.
