Have I just been lucky so far ?

Ok, I've had a variety of fish for the last 15 years.
Currently I have two small Oscars, I've had Oscars in the past and I'm returning to them because its been awhile.
Past fish include African Cichlids(various types), Loaches, Red Tailed Sharks, Water Turtles, Frogs ETC.
You get the idea, I've had a wide variety of fish.
Now here is my question - I never keep track of HP balance/ Amonia levels.
Basically I change the water on occasion and keep an eye open for anything that looks out of the ordinary.
I do add ike guard when doing a water change, which is one of the few extras that I do.

Other people seem to be going through so many steps and checking every little detail on a daily basis and still having problems.

Have I just been lucky so far ?
How are my fish able to thrive with out these needed steps ?