Everybody is different, where one person may need to carry out a water change once a week, somebody else with a similar setup may need to do it twice a week.
How many fish have you got? How often & much do you feed? What kind of filtration have you got? How big is the tank?
I prefer temperatures between 26 and 28°C. I change between 40 and 50% of the water. My nitrate levels are normally between 20 and 30 ppm when it comes to WC's which is good.
You shouldn't really need to vacuum the tank more than once a week. Obviously if you are feeding enormous amounts of food then your tank is going to get dirty that much quicker.
If you have got a good filtration system, don't have too many fish, carry out regular tank maintenance, then your tank should stay healthy.
It really does boil down to tank size at the end of the day. If somebody insists on keeping large messy fish in a small aquarium, expect to have to carry out lots of tank maintenance.