All recorded CDR’s have errors, which is why discs with critical data are recorded with supplementary error correction. As long as the errors are correctable, there will be no effect on the accuracy of the content. If sectors containing errors have to be read again, the read speed will decrease to enable rechecking and error correction to be accurately applied. If uncorrectable sectors are present they are not readable, and some or all of the disc may not be accessible.
It is highly desirable when recording to match the media, burner, and recording speed so that there as few errors as possible. Discs that are burned with many errors (even if correctible) from their inception are much more likely to have some sectors degrade to unreadable uncorrectible sectors.
Using the CD Speed CD Quality Test, the yellow spikes reflect correctible errors (red is uncorrectable). Ideally there will be no yellow spikes. This doesn’t mean there are no errors, only that they are below the reporting threshhold. If there a few minor spikes of low amplitude, this is usually acceptable. With a careful matching of media, burner, and record speed there should be no yellow error spikes, and this outcome should be the goal.