Distinguish Between Efficiency and Effectiveness
Establish a philosophical framework for your overall approach. When it comes to getting the best results, there are two similar, yet distinctly different avenues you can pursue:
You can strive for maximum effectiveness.
In other words, you want the maximum possible outcome, without regard to the price you'll need to pay in time, energy, money, or impact on the rest of your life. If ingesting 100 grams of carbs immediately upon finishing your workout is .03% more effective than waiting until you get home, you'll consume those carbs at the gym.
If training biceps and triceps four times a week is marginally better than three times, you'll take the former option, even if your girlfriend complains that you never spend any time together because you pretty much live at the gym.
You're more about maximum efficiency.
If research shows that lifting four days a week is only slightly more effective than three, you'll still train Monday, Wednesday, Friday. If stopping two reps before failure is nearly as good as redlining it, you'll leave a few reps in the tank.
In other words, you've chosen to look not only at the results, but also the costs of those results. If significantly less work, and if stressing over details gets you 85% of the results you'd get if you went balls-out, that strikes you as a good trade-off.
Neither approach is objectively wrong or right. It's just a matter of personal philosophy and goals. When you're clear about your training target, you're much more likely to reach it.