In Line Water Filter

Lot's of variables that can affect filter quality that are hard to judge. What is the quality of the water being filtered ? What elements in that water are being filtered ? Does the filter cartridge contain anything to kill bacteria ? Filtering chlorine is one thing vs. dirt/sediment/iron etc. and all will change the filters ability to filter. In my opinion I would go six month intervals, I base that solely on not knowing if the filter has an anti-bacterial feature. A charcoal/carbon filter will basically filter until it is clogged. But that does you no good if it is a breeding ground for bacteria !