Assessment should be regarded as an ongoing activity throughout CBT-I, rather than a single event at the beginning of treatment. It is essential to continuously assess for changes in sleep patterns, varying levels of sleepiness, and client adherence, and remain open to emerging evidence. Consider the following example: at the sleep assessment session, you meet a 41 year old female with average body habitus, no knowledge of whether she snores, no hypertension, and a normal, albeit elevated score on sleepiness scale. Such findings are not particularly suggestive of sleep apnea. If, however, over the course of treatment, there is high adherence to treatment, a very quick sleep onset latency, even when the time spent in bed has been lengthened, there are complaints of subjective sleepiness and a report of many very brief wake-ups in the second half of the night, one should reconsider whether there may be an occult sleep disorder, such as sleep apnea.