That being said, are you willing to risk a batch? I would be, S.Cerv might not be.
You're talking about a guy who spends a C-note on yeast strains that have almost no brewing data. I could be ordering and pitching a brewery contaminant for all I know.
With that said, I have pitched six month-old crops without making a starter; however, it's not something that I would recommend. I usually wake a four-month old crop up before pitching it. That way, the viable cells can be separated from the dead cells.
I'm definitely no microbiologist, but many of my jars get the "sniff test" when I pull them out of the fridge. First, they should look ok- no black spots, weird things, etc. And when you open it, it should smell like a yeasty beer smell. If there is any weird odor- sour, fecal, etc, but plain old "not right"- the jar should be discarded.
I try to use my jars relatively quickly, but sometimes they sit too long and I don't have any pangs about tossing them if they aren't right. It's not scientific at all, but as a long time brewer sometimes just a "not right" feeling is as good as a microscope. Other times, well, no. But the sniff test will definitely tell you if it's "off" without a microscope, as there is no mistaking severe problems (like 'fecal').