A filter change is recommended every 6 months.
Your filter can effectively filter up to 1000 liters of water.
That will come to one filter every 6 months, if you use an average of 5 liters per day.
Water quality can also affect the lifespan of the filter, especially if using hard water (bore water) through the filter.
Even with low usage a filter change is adviced at least once a year.
$65 every 6 months =
$2.5 per week
0.36c per day
0.07c per liter
$65 includes filter & service
$45 filter only - DIY