I feel like folks are tap dancing around the border of the parts of the topic that fall under the "behind the counter" category, so I'm going to jump over for y'all.

Adderall and related schedule II nootropic stimulants are amazingly effective for their intended roles and when used at medically indicated dosages (rather than doing the abusive equivalent of swallowing a bottle of no-doze caffeine pills) are among the safest drugs for which it is possible to get a prescription, in that any side effects induced by taking a prescribed dosage will cease soon after cessation of the medication.

That being said, the view that they are study drugs is not quite a complete or accurate picture of their cognitive effect. A more accurate but still imprecise view would be that at the correct dosage, adderall and family "reduce the activation energy needed for attentional engagement" and "increase the baseline activity level of higher order planning faculties" (that is, every time you have a "I should do this vs i want to do that" moment and chose the "should do this" path, you are actively using the higher order planning faculties).

These effects are why adderall et al are great for treating those who have ADHD, ie those who have a dysfunctionally high activation energy for attentional engagement in tasks, and perhaps due to insufficient activity of those higher order planning faculties that influence moment to moment behavior also have impulsive behavior and all the externalities that these difficulties imply. Study drugs they are not, they just happen to help you focus on what you really really want to focus on if you try hard enough.

If you do not have much in the way of excessively impulsive behavior or difficulty focusing on what you really really want to be doing when both well rested and in shape, then you do not stand to gain much / anything from using them.

If you're not well rested, either drink some strong tea (because caffeine and theanine are great!) or go to sleep, and if you're not in good physical health, go fix that with some exercise instead of whatever you'd be procrastinating with because that affects your quality of life and net productivity more than getting another hour of work done. Adderall et al will not make you better at focusing just then and there.

I feel that people often lose sight of the fact that while the human brain can do amazing things, there are limits. With nootropics such as adderall, even a slightly higher dosage in the normal dosage range can essentially result in a sort of unpleasant "overload" of your ability to direct your focus. I suspect this is a miniature version of whatever those who recreationally abuse these stimulants experience, in which case they must be idiots because i don't understand how that could be pleasant.

if you have allergies that can be made tolerablish without something like zyrtec or claritin and you have work you need to do, don't take the allergy medication, they have essentially the exact opposite (I believe antagonistic is the term used) cognitive effect of prescription dosages of adderall et al.

Obvious caveat, everything I say is merely reflects my personal experience managing adhd, reading up on various bits, and observing how many people work. Also, it seems that at least anecdotally that the manner in which a person with unmedicated adhd structures and approaches work is radically different from how everyone else does so, and that part of the adhd treatment process is sort of a (think HeMan) "By the power of ADDERALL, I shall use my newfound powers of ease of attentional engagement to devise more effective and efficient ways of structuring how I approach work"

theres probably things i'm overlooking, omitting, oversimplifying or exaggerating, but hopefully this has some useful information for someone.