We had a couple of threads EXACTLY like this one throughout the last week.
Popular consensus was that less dosing/smaller dose amounts = less water changes.
Testing will help you achieve the right balance.
Use the search button next time!
Test kits are not required to find "balance".
That was one of the main points EI since few people bother to test to begin with. Adding to that, people also never/rarely used standards to ensure their test kit readings were accurate to begin with, most still do not, they just assume.
I have no issues with test kits, I've used them and developed quite a few methods myself specific to planted tanks.
The problem is more "human".
We still are going to do a water change, we still are okay with that and caring for the tank and fish in a good manner. 50% is an arbitrary %. It was chosen because it made the math build up easy. This was BEFORE dosing calculators and modeling graphing charts.
Folks should start at a non limiting level and then slowly reduce the dosing down till they see a negative effect on the plants(perhaps the best test kit for the human issues), then bump back up to the last highest dosing routine.
Or you can simply do the 50%, dose the ferts and not worry and fuss.
I change about 70% weekly and clean the tank well, trim etc.
I have about 440 gal worth of aquariums, takes me about 2 hours once a week. Hardly difficult chore for that much aquarium.
Do I test?
I did for somethings in the past, but mostly light/CO2 and 95% CO2, these are far more important and manageable than nutrients.
I do few water changes on the non CO2 tank, and maybe once every 3-4 weeks on my iwagumi hairgrass tank as the hair grass just does not consume much ferts. It also has low light.
Balance is more than nutrients, it includes CO2 and light 1st, the last part would be the nutrients in terms of "balance". Plant species, fish, biomass etc, food type, simple care of the scape etc, these things also regulate whether you might want to do more water changes, or algae, poor plant growth etc.
Water changes are one of the simplest most effective management tools available. Make them easy and if you bother to do them, go big % wise.
If you know yourself well enough and do not like doing them, then go non CO2 and/or low light, low maintenance set/scapes. Many want these nice scapes that require work, and also want/or just buy.....high light, then do not want to do much to keep up on it, that is not realistic.