One of the most common concerns I hear from my customers is that they're using oils for sleep, but still waking up after about 3 hours and then can't get back to sleep, without obvious sleep disturbances (such as bladder issues, etc.). What I usually find is that they're only applying oils topically, or they're running their diffusers in such a way that they only run for a few hours.
Oils absorbed through topical application will typically metabolize and be out of your system within 3 hours, so if you're only using sleep supporting oils topically, you may find that you're waking after just a few hours.
Depending on your diffuser, it may have a "low" or "intermittent" setting that allows it to put out less mist at one time so it runs longer. Check your diffuser's manual to ensure you are setting it up to run for the length of time you will be in bed. This will keep the oils flowing so you're more likely to stay asleep.
My advice: make sure you're diffusing AND applying topically. The topical application can help you relax quickly so you can GET to sleep, while the diffusing will last through the night so it can help you STAY asleep.
Of course, explore any other reasons you may be waking, like bladder issues, pain, worrying, bad dreams, snoring partner, or other sleep disturbances. Chances are, there's an oil to support that too!