Well, ferts tend to be the easiest item, light can be also.
That leaves horticulture, aquarium care and then ....CO2 mostly.
CO2 gets everyone at some point.
EI just makes the ferts independent for plants, algae etc, so you can focus on other stuff. You can do more frequent water changes, more % etc on newer tanks, generally the 1-2 months after set up, say 2-3x aweek water changes, then taper off to once a week, or depending on the tank etc, 2-4 week intervals. I can go months, but I just like to keep a good habit and get in the tank and clean things up.
Non CO2 tanks generally get no water changes for months.
Some argue that EI requires "frequent" "laborious"(or any other disparaging adjective they can conjure up) water changes, which is frankly a bold faced lie. I use 50% weekly as an example, never a requirement. The user can modify to suit a number of trade offs and goals. If you have to lie to sell your dosing method, I think you need a better method. Dosing is moderately important, but many hobbyists place a much larger importance on it than say CO2 or light, which are by far, the much larger factors and drivers of plant growth.
A good article that explains this well (and ferts a little, they used non limiting ferts, similar to EI):