Do you have plants? Nothing keeps glass spotless like a day or two of darkness!
I do 75% water changes weekly, but unfortunately I have about 10ppm nitrates out of the tap, and no plants, so algae is inevitable. But, once in a while, I shut the lights off for a couple of days and it's all gone. Otherwise, I scrape it, combination of a magnetic scraper (awesome tool, you should get one), and a credit card. Stirring the substrate keeps the algae off of that, and beyond that it's the rocks and the back wall that get bad every once in a while. When that happens, again, a blackout session. I do it once every couple of months. Gives the tank a "lived in" look without a "Do you ever clean this?" look.
-John