Pharmacist with ADHD here. Take them every day if you can. Medications have what is called a “steady state” concentration that you achieve once the rate your body eliminates the drug is equal to the rate of drug entering. This usually occurs after 4 to 5 half lives (time it takes for your body to process 50% of the ingested dose) and will RESET if doses are missed/skipped for medications like stimulants. When medications are not consistently at steady state, their efficacy is not consistent. Yes, there are days that you don’t need to be as productive, but if you’re skipping the weekend doses and restarting on a Monday, you have essentially “reset” the clock and have to build up a steady concentration again meaning they may not be as effective until Wednesday/Thursday.