I have to respectfully disagree with Slipknot1 about the "audio optimized" blanks. The only difference between the "audio" blanks and the rest is that the "audio" have the coding to work in consumer class non-computer cd recorders. The extra money goes to a fund to pay royalties, or something like that.
As to the problem, what do you mean by "jittery"? What does it sound like? Jitter is an often over used and misunderstood term. Jitter is the annoying tinny/grainy noise which is caused by clock errors created in the A to D or D to A process. It is highly unlikely that a disk would play fine one day and then have "jitter" a few months later, since the jitter is caused by the DAC, not the disk. If your original source was also digital (ie, another CD), then your DAC or CD player can be the only source of the jitter.
If you are hearing scratchy noise or pops and clicks, then you are experiencing drop-outs, which is possible. CD-R's are made with a softer "wax" than the professionally produced CD's. As such, they are more heat sensitive and, depending on storage conditions, they may degrade. They are certainly not so heat sensitive as to be delicate, but over time they can degrade.
Hope this helps.