For the question of does amphetamines stop working...
It depends on the situation. If one takes amphetamine as prescribed and the patient doesn't perceive the idea of working (especially when they are trying to find the initial starting dose), as the stereotypical recreational side-effects (side-effects because they are in terms of therapeutic action), like an increase mood/euphoria, intense hyperfocus, hyperactive body sensation (tweeking), feeling of overconfidence, increased sociability, reduced appetite, etc, then no the therapeutic benefits do not stop working in any appreciable time. Now it seems, particularly on bluelight, but also in those I've met who aren't even recreational drug users, that when those side-effects begin to disappear, they feel the drug isn't working any more. However, therapeutic use of amphetamine continues well beyond when those side-effects aren't apparent. One can remain at the same dose for years with out any lose in efficiency of the actual expected therapeutic effects. People just rather not admit it and chase after the high. Like with majority of therapeutic drugs, they are supposed to minimize the symptoms being treated for, allowing for "normal" functioning. One doesn't need to be tweeking to maintain a normal level of concentration. Your not expected to be able to sit down for 24 hours barely moving hyperfocused on one task. That is beyond normal and you'll notice the quality of work after a certain point continues to diminish as time goes on during the hyperfocused period. Like I said, amphetamine use (especially higher doses) can increase the number of mistakes made in a given period relative to no amphetamines. Doctors do not often enough explain the drugs they are prescribing and what to expect, resulting in users of benzos, amphetamines, opioids, etc. to constantly be over dosed. Now I know I may catch strife for that, but let me note, I'm not talking about every user. Though, if you are not taking your prescriptions as prescribed, like snorting/IVing opanas, taking extra xanax every so often, adding street drugs on top of prescribed drug, you are going to build up tolerance a hell of a lot faster resulting in a lack of efficiency of the therapeutic drug in question. Yes over time, and there is no set time for any drug on how the tolerance will increase, the efficiency will decline, but the patient more often than not will be better off extending out the current prescribed dose until most of the therapeutic benefits are gone (until they start to lose the ability to perform their daily functions). If you increase your dose every day that you feel the pill decreased it's efficiency you'll end up in a multitude of uncomfortable situations. The number of negative side-effects increases the higher the therapeutic dose is, the efficiency of the drugs will continue to decrease till you run out of options to treat your problems, and you are likely to have created a dependence or worse a addiction to the substance.
Methadone (for some conditions, maybe not MMT, I don't have experience with this) is the perfect example of a drug maintaining it's efficiency even though the pleasurable side-effects disappear. I've been on methadone for coming up 7 months now and I don't get anywhere near the same level of a buzz if you will that I get now. Thats not to say that the condition that it is treating isn't being treated. My RLS remains treated with the exception of situations that would exacerbate the RLS on a drug or not (for example like airplane rides in economy seats)
Of course there are always exceptions to the rule, but in general therapeutic doses of amphetamines do not lose their efficiency that fast. It would generally take countless years and years for the drug to stop working. There are individuals who remain on amphetamine like substances for majority of their life with out it stopping working.
If it wasn't for my occasional abuse of amphetamines, 30mg a day would and has worked for me for 2+ years with out a single dose increase. When I've abused it, by not following the directed dosing guide, the efficiency was lost fast. However, with the appropriate supplements, diet, exercise, and break from use, I've managed to get the efficiency back to where 30mg a day is all I need.
Some drugs are different though, so this doesn't always apply and why you need to discuss your concerns with a doctor if you're afraid of a lose of efficiency. I know my dissociative tolerance will not decrease in any noticeable or respectable amount after my use of DXM, Ketamine, 4-MeO-PCP, and MXE.
u ask billion questions so ill just answer one: Can Adderall stop working?
The answer is yes. The military rejected the drug as unreliable. Not only ADDers reported that it can "stop working" but regular soldiers on flight missions reported the same thing and they didn't have ADHD. If you want something that works all the time like a Swiss watch, use Dexedrine, pilots call it flight go pill. 10,000 pilots used it 10,000 times and 10,000x10,000 the pill worked, didn't fail a single time.
Problem is, some ADDers find dex too soft and like Adderall better for the "kick in the pants" given by the 25% levo
The military finding amphetamines unreliable doesn't mean that the drug stopped working. The way they were using amphetamines was the problem. Like I said, abusing a drug will always result in a loss of efficiency and the way they were using the drug was in a very negative fashion with negative side-effects on the pilots which made it's use unsafe.