I know this is pretty old but thought it was about time I chimed in...
I've been using an increasing variety of *racetams and other nootropics pretty much daily for >2 years and have a few takeaways to share...
A few words on dosage:
I will refrain from specifying dosage since it varies from person to person and drug to drug. It should always be just enough, 'nuff said.
Reading around the web I gather that most users play around with pretty high dosages, often claiming super-human feats of cognition or learning. The few times I've tried more than my usual, I've come away disappointed. I get pretty dramatic benefits from taking just enough for it to work. Doubling or even tripling that "just enough" dosage can be interesting but it's not particularly helpful... *Racetams are subtle so you can't expect to really "feel it kick in" like caffeine or amphetamines. If you take enough to feel a solid kick in that probably means you took too much and you're wasting your money. Does drinking 8 cups of coffee improve your productivity? Not really, and taking several grams of oxiracetam won't either, especially long term.
All this said, most of the research I've done indicates that it's not particularly dangerous to mega dose. Long-term daily megadosing is another story. While the drug itself poses little/no risk of toxicity, you will end up with other problems like adrenal fatigue, anxiety, antisocial behaviors, insomnia, malnutrition, etc... maybe even psychosis. Perhaps most important you'll be wasting your time and money because you aren't likely to notice any super-human benefits that can't be dismissed as placebo and you'll be developing serious tolerance and/or dependence. Which reminds me...
Let's talk about tolerance.
If you're the kind of person who needs to feel a "kick" from whatever drug/supplement you're using to be satisfied, you will surely encounter tolerance. This can be remedied with cycling (look it up) and AFAIK tolerance is not permanent unless you've actually damaged your brain, which you'd have to be an idiot to do with *racetams. A few weeks or months away from the drug and you should be able to get your old results again.
However if, like me, you're quite satisfied with the minimum effective dose, you won't likely develop significant tolerance. I've only seen tolerance to a couple of the stronger ones such as pramiracetam and phenylpiracetam and even then only a tiny bit. It levels off and I continue to receive ample benefit from a steady dose as long as I'm not looking for a "kick".
If you must get your kicks, have a cup of coffee or 5-10 mg of amphetamines (AKA Adderall) or methylphenidate (AKA Ritalin) along with your *racetam. Mix the *racetams with caffeine and Ritalin and you'll be able to get your kicks on dosages well below what could lead to tolerance and experience a smooth, steady flow of cognitive surplus. Which leads us to...
Stacks, waves, and it all comes together...
My "nootropic" stack consists of little more than *racetams, CDP Choline, and L-Theanine. You might count magnesium, the occasional fish oil, b-vitamin, or other nutritional supplement.
I also eat very healthy (somewhat "paleo") and exercise several times per day.
However, I tend to consume 1-3 stimulants along with my stack. Some combo of coffee and tea, ginseng, Ritalin, and Adderall. Always in fairly small dosages. The combination is where I get any "kick" I need to feel. This keeps things safe, smooth, and minimizes risk of side effects or tolerance.
It doesn't stop there. I've used a variety of mildly psychoactive substances every day for many years now and really fine-tuned my approach. I was prescribed Ritalin for ADHD as a child and have been on and off of it for about 20 years. At one point I was taking 40-60 mg per day which, IMHO, is absurd, especially for a child. Today, I take about 5 mg of either Adderall or Ritalin 1-3 times per day almost every day of my life. At this dosage I never develop tolerance or any notable side effects. I know, this isn't about Ritalin, but it plays into my approach.
I've also used marijuana for about 15 years and alcohol for about 12. These days I use them almost daily. So, what of it?
Waves people. Waves. My mood and energy levels persist in a pretty predictable sine wave every day. I wake up slowly and stretch and do a little groggy exercise with a cup of coffee, some kind of *racetam, and usually and a little Ritalin/Adderall. I'll usually take a second *racetam dose around noon +/- 2 hours, along with some tea and perhaps more Ritalin/Adderall. In the evening some time between 3:30 and 7 I start to calm myself with some Kava, marijuana, or alcohol (or a combo) and then take no drugs for at least 2-3 hours before bed time.
The wave ensures predictable, smooth effects while reducing the risk of some of the side effects mentioned above: adrenal fatigue, anxiety, sleepless nights, etc... Anyone taking nootropics to try and work 16 hour days and sleep as little as possible is doing life wrong. You cannot do that long term. Long term safe, effective use of these and any drugs requires balance and harmony.
The idea is to give yourself a predictable cycle of mania and depression that never peaks too high or dips too low. Psychoactive thrill seeking is not sustainable. If you want to keep at it safely, daily, and for many years to come then just forget about the rush and embrace the wave. Enjoy the wave. Ride the wave. Surf the wave of life day after day. Get your thrills from experience, not substance.