A couple of long standing deductions have either not been extended to 2015 or have been significantly reduced.
The Mortgage Insurance Premium deduction that has been around for years is, as yet, not deductible for 2015. That does not mean that at some point Congress will act to extend the deduction or change it in some other way, but with all of the extenders they approved early in 2015, Mortgage Insurance as a deduction was not one of them.
The Section 179 deduction for accelerated depreciation in the first year of service for new assets was $500,000 for 2014. For 2015, the deduction goes back to $25,000 on a maximum of $200,000 of new assets placed in service. So that deduction is severely limited compared to the last several years. So you may want to keep an eye on legislation being passed in 2015 to see if they raise this limit again. Until then, do not assume that you will be able to depreciate 100% of new assets you place in service during 2015 beyond the $25,000 maximum.
Most years, we have the same old deductions that have been around for years. You may want to keep your eye on 2015 as the Republican Congress may change directions on a few of them.