I fully understand training smart, however, that is not an excuse to train at an intensity less than your best. Few can train with top level intensity day in and day out. Those that do, and are mentally and physically tough, are usually the ones winning.
The most important aspect of training smart, is how you live outside of your training. What you eat, when you eat, how much sleep you get, what you are and aren't drinking, what your smoking...and why. There are exceptions (real champions of your sport-UFC Champion, Black Belt Pan Am/Mundial Adult BJJ Champions, Olympic and World Champions, NCAA Champions), and when you are one of those exceptions then you can do what you you will.
However, if you have a gol (sic) to be your best, then everything you do must be in line with that goal. It will be extremely difficult, you may hate it at times, but the inner passion, the love for the sport, and mental and physical toughness that doesn't allow you to quit drives you by the hour. That same drive and passion also stops you from doing the things that will take you a step back from your goal.
In the end no one but yourself will kow if you really did everything you could have, and didn't do the things you shouldn't have. Hopefully, when it is all said and done, you will have no regrets - regardless if you made your goal or not - because you truly poured your heart, soul and body into your pursuit.