I also change water because I am cheap. A 200 gallon box was $32, or $8 a bag - now I bought a pallet in 2014 for that cheap, I am almost out of those boxes and the next batch will be about $40-41 a box. Where else can you do all of your routine maintenance for $8 a month? ...or $10 a month in 2018 dollars? It does not get any cheaper than this, IME.
Send in a few Triton tests and buy some of their supplements and I can change water for a few years in what some people spend in a quarter.