If you take a longer trip at least over a week then you can get by with shorter days at parks each day.
We find using the extra magic hour in the morning most helpful. You can train yourself to do this by practicing at home just before you go to get up earlier. Then, it won't be such a shock. You can accomplish a lot in that extra hour when the general public is not there. You work your way to the back of the park in that first hour and you have some good time in the back of the park before the general public catches up to you. Then, you use your three Fastpasses on rides, not shows. If you get done early with a fastpass then take in an attraction on standby but watch the time waiting to make sure you don't screw up your other Fastpasses. We then break for lunch for a rest. After lunch if you decide you can continue, get a fourth fastpass while eating lunch. Doing shows, not rides in the afternoon provides for more rest. With most shows if you get there ahead of the show time you will get in without a problem. You may not have the best seats, but it's doable.
The other approach is to take an afternoon break, but do it early; so, you can get back to the park for early evening. If your kids won't take an actual nap this may not work. This will involve two commutes and that can be harder on a person. Make sure your Fastpasses are used up in the morning; so, you can go for a fourth fastpass when you return in the evening. Now, you can enjoy fireworks and maybe some late extra magic hours.
Finally, I don't think there's a wrong way with visiting Disney. For us, it comes down to economics. We want more park hours to get our money's worth. You pay for park tickets whether you stay in the park for an hour or ten hours. If long days at the park are tough for you, maybe consider alternating a long day with a short day the next day. Obviously, choose your favorite parks to be the long days.