When applying the 168 Allowance switch, only qualified assets placed-in-service in the year entered will change. See How to apply 168 allowance.  

Qualifying assets:

• Activity Code is A (Active). (Assets that you haven't Transferred or Disposed.)
• Placed-in-Service date is 09/11/2001 to 12/31/2004 or 01/01/2008 to 12/31/2027.
• Depreciation method is a MACRS method or SF.
• Property type is P, A, T, Q, R, S, C, E, or F.
• Estimated Life Less than 25 years (certain properties with a 39-year life do qualify)
• Business use is 51% or greater.

Dates when 168 Allowance Percentages apply:

• Assets Placed in Service between 09/11/2001 to 05/22/2003 take 30% allowance
• Assets Placed in Service between 05/23/2003 to 12/31/2004 take 50% allowance
• Assets Placed in Service between 01/01/2008 to 09/07/2010 take 50% allowance
• Assets Placed in Service between 09/08/2010 to 12/31/2011 take 100% allowance
• Assets Placed in Service between 01/01/2012 to 09/27/2017 take 50% allowance
• Assets Placed in Service between 09/28/2017 to 12/31/2022 take 100% allowance
• Assets Placed in Service between 01/01/2023 to 12/31/2023 take 80% allowance
• Assets Placed in Service between 01/01/2024 to 12/31/2024 take 60% allowance
• Assets Placed in Service between 01/01/2025 to 01/19/2025 take 40% allowance
• Assets Placed in Service on or after 01/20/2025 onward take 100% allowance