I have a fitbit but it doesn't really help much in tracking narcolepsy symptoms unless you're just looking for more insight into your sleep every night. I mostly use it to keep me on a stricter sleep schedule

All the things do is prove to me that i have sleep past regularly daily amounts of sleeping in a day (for example 8 hrs is normal i sleep upto 15 hours

I use sleep apps on my phone & watch to hack my sleep cycles (or lack of them). Sleep as Android is probably the best one I've used if you only have a phone. You just need to leave the phone near you when you sleep so it can record your movements. I recently switched over to Samsung Health when I bought a new Galaxy Watch 5. The watch as some great sensors that I find useful. Not only does it monitor my sleep cycles in great detail, but also tracks my O2 levels, heart activity, and snoring while I sleep. Recently, it alerted me that that my deep sleep periods were woefully low. I let my sleep specialist know & changed my routine which seems to have helped. My deep sleep cycles are almost back to normal. I would advise anyone with narcolepsy to find a way to monitor your sleep. Whether it's your phone, your CPAP app, or a watch, knowing your quality of sleep gives you tool to help manage your condition without always turning to meds.

S3 are much more accurate than the fitbit watch

If you want a bit of info on what sleep tracker you are better with. Please allow me to tell you that I have Samsung s3 and when I am sleeping it monitors this but when I am dropping off to sleep that is when it will start monitoring the light until I'm relax and in deep sleep they are brilliant