I used to keep fish. I loved learning about the nitrogen cycle, setting up the co2 diffuser, balancing tank parameters, designing the filtration system, researching, purchasing, and acclimating exotic fish. Fascinating, colorful and compelling. But once the set up was done and I had a mature tank I was bored and dreaded basic maintenance. The fish didn’t deserve a subpar home so I did my best, but when we moved and sold the set up, I never went back.
It takes about 5 half lives to clear 95% of a substance from your system. A quick google says the half life varies from 5-21hrs, so even if you’re on the slower end, a week should do it.
If you’ve been on it for a very long time then your CNS may need more time to get back to baseline, but you probably don’t need a perfectly clean slate to assess if a new medication works for you. Plus, switching from a nonstim to a stimulant is a totally different class of drug and you should feel the effects of a stimulant fairly quickly.
Just make sure you time and dose correctly to avoid messing up your sleep.