In freshwater tanks water changes should be done weekly in most cases. While in most cases 10%-15% is fine i prefer 50%-75%+. In larger tanks that can be a lot of water. Using buckets is no fun at all and can cause people to be disinterested in their tank.
To save time and effort I suggest a water change system. Python water change system along with several others hooks up to a sink or hose. I prefer a hose leading outside. I use my old tank water for the grass, trees and garden. The only problem with these type of system is they are designed to leave the water on to create suction. By draining outside or to lower drain you are able to turn the water off thus save water.
Another option and my personal favorite is to use a pump attached to the hose. This eliminates the need for the water to be kept on like the python. It also drains the tank faster. When you have many tanks like me this can be invaluable.
For future fish geeks/nerds that end up with fish rooms an auto or semi auto water change system is the way to go. There are countless ways to set up an auto/semi water change system. If you need help fining info on some please email but a quick google search will do wonders.