Value of Cisco certifications
For someone that is looking for their first networking job, the certifications help to get your foot in the door with companies:
You might have not enough real life experience, but the certifications tell that you spent time and effort to study the technology.
On the other hand, once you have 10-15 years of experience at 1-3 companies, the certifications might become less important. If you would apply to a job somewhere, they'd probably think those years of experience are more important than the latest certification. In this case, it might be better just to learn the technology and don't care about certifications too much:
If you decide not to care about new certifications, I would keep them valid. Just do the equivalent exam of the track you already passed. For example, if you did CCNP R&S then just do CCNP ENCOR of the Enterprise track.