"Gaining a qualification gives you that qualification. It’s the ongoing use of these skills and knowledge that keep it current. However, job requirements and industry trends changes. Therefore Training Packages are regularly reviewed to ensure they reflect the current standards required for the job."
If you look at the history of the TAE. The first TAE qualification was endorsed in 2010. The new qualification TAE40116 was endorsed in 2016 and people who held the old qualification had until 2019 to upgrade their qualification. For most people the upgrade as a combination of RPL, Credit Transfer, some gap training and 2 additional units of competency.
There’s no guarantees on how long your TAE will be current for, however, ensure you keep up your professional development and industry currency and the transition / upgrade to any new Cert IV is not going to be overwhelming for you.