My current MCSD (Web) certification will expire in December this year. I think one option is to pass 70-494, which will renew it for 2 years? I'm a bit confused by the new AppBuilder certifications as well. I'm primarily a .NET web-developer.

What are other people with MCSD (Web) planning to do?

Also, when will I become eligible to take the renewal exam? Is it at 6 months before expiry?