I get this question a lot.
If you have a good vocal teacher, he or she should help you identify the physical feeling associated with the ‘right’ way vs. the ‘wrong’ way.
Also, if it feels more relaxed/lifted and ‘easier’ yet the sound you make is better, you’ve probably just eliminated a flaw. You see, Vocal Freedom (the ultimate goal for singers) is exactly that – it is a very liberating feeling, causing no pain, almost effortless in the actual creation of the sound.
What should exhaust you is an ultimate connection to the music, and your efforts to become a conduit for your audience. You’ll know from their reaction when you get that right!