(Ask 6 times) Using tap water to clean Dream Lenses

The older child in sixth grade is wearing contact lenses.

After visiting the ophthalmology clinic for the first time and purchasing the correct lenses, the instruction leaflet I received stated to clean with tap water, so I have been wearing them after cleaning with tap water until now.

I went for a check-up, and they said I need to rinse with saline solution again? I wondered if I had been doing something wrong all along, so I asked. They said there have been recent cases of infection from rinsing with tap water, so they recommend saline solution. If I rinse with saline every day, I don't think one or two bottles will be enough. Do all people who wear daily lenses use saline solution?