3 gallon Betta fish tank

I have a betta fish in a 3 gallon tank without a filter. How often should I be doing full/partial water changes? I am a little over whelmed because every time I try to research it I find a ton of different answers... I plan on getting a different tank possibly a 5 gallon tank with a filotration system. How often would I do full/partial water changes then?

Ya, a 5 gallon tank would be much better. Also, without a filter you will need to do a water change every 2-3 days. With a filter and a bigger tank, like a 5 gallon with a good but not fast fiter, bettas cant swim and will striggle if there is a current, maybe like once every week.

I need to do a complete water change every 2-3 days? When I get a 5 gallon tank with a filter, how often will I need to do complete water changes?

Changing all of the water at one time may create sudden changes in water parameters. Such changes are dangerous to the fish.

Without a filter, it's important to feed no more than gets eaten in a couple of minutes, remove any uneaten food using a turkey baster or small syphon, and change about 30 percent of the water every two or three days.

For very little money, you can buy a miniature air pump, some plastic tubing, and a sponge type filter. The sponge filter will improve water quality and circulation. In addition, it will help transfer beneficial bacteria colonies into the new aquarium.

Ok thanks! How often do you have to change the water if you have a filter? And do you do part or full water changes?