I've never pursued a certification. On the other hand, I have no formal electronics training either. The company I work for didn't think it needed anybody who knew electronics when I started doing work here some 23 years ago. Since nobody else knew electronics, I simply started applying my mathematics background and managed to entrench myself, not as the only one who really knew electronics but the only one who would roll his sleeves up and grind out transfer functions, motor models, PLC programs, and simulations of just about anything electronic, magnetic, pneumatic, hydraulic, and/or mechanical. I'm now dipping my toes into acoustics.
I think given current economic conditions I would get the certification to help with getting the first job. If you prove your mettle after that, the CET won't mean half as much as the 2 year degree and the experience so I wouldn't go so far as maintaining the certification unless you end up looking for work again. While self-employed (pimping myself out) a few years ago, I picked up the A+ and Net+ certifications and they really helped with my scaring up contract work at Staples and various local manufacturing facilities. Once I was officially reemployed, I let the certifications lapse.