yep, that's right.
quite possibly the dullest question ever to have been asked - and not just on this forum.
I live in a hard/soft (not sure which, don't care) area, so only have to change the filter every few months.
in fact, the water is so good out the tap, I probably don't even need a filter.
I like to have a jug knocking about tho - encourages me to get my 2L a day.
feel free to chip in/deride - there are many options