the size or the tank, stocking levels, feeding routine and filtration play a large part in proper maintenance. Just because the LFS guy never does waterchanges on his tank doesnt mean that will work for you. also, remember there is a small conflict of intrest when discussing maintenance with the guy who sells you your livestock.
grab some test kits so you can see whats going on with your water chemistry and go from there. start with nitrate, phosphate and alkalinity.