yep, water changes are good.
however, if you have an established set up with tons of lr and such, then you won't need one as often.
I did monthly, now I do weekly or every two weeks or whenever. (I have tons of lr in a 20gl with one star and no fish). In my 10, doing a gallon a week is no big deal, takes no time at all. with 75gl, it takes more time BUT I have more room for error.
When my 75gl was up, it was every 2-3 months, BUT i had lots of lr and very low (2 fish, lots of inverts) bioload. I was in school and that's all I had time for.
Test your water or take it somewhere and have them test it. if your nitrates are over 5, then do a water change. if you see it takes a month for them to get over 5, then do it once a month.
High bioload, imo equals more water changes.
Water changes decrease nitrates and replace trace minerals you can't test for.