How do YOU do water changes?

Welp, i use tropic marin pro reef salt. They claim to have all 70 natural sea elements in the correct amounts to the point where its nearly impossible to distinguish natural sea water from their salt mixture. When i got into the hobby i was told wc were important, ive stuck with it since the beginning. Only reason i miss a wc or 2 (which hasnt happened in years) is cause i was lazy. Why would neone choose not to do a water change? If its to save money id say this isnt the hobby for them and what would anyone really be saving? I do 7 gallons a week on my 90 and bucket of salt which makes around 180 gallons @ 1.025 ($70.00) lasts me roughly 6 months. Whats that 11.50 a month to do waterchanges?