It really up to you and your fish load, i do 25% once a week but i also keep my tanks understocked have lots of plants and only feed like 3 times a week.My tank is always kept super clean with weekly water changes and trimming dead plants and removing all dirt etc.
Currently I do around a 30% water change would you suggest I do 50%? Also, should I do even even more than 50% at any point?
Only time i do larger water changes is if my daughter dumps all the food in at once