Pur water filter... when do I change it?

I have a Pur pitcher. How do I know when to change the filter?

The website says...

%26quot;All PUR filters come with a built-in Automatic Safety Monitor鈩?gauge so that you'll know

(and even in advance) when it's time to change the filter.%26quot;



This tells me nothing.

When I pour water, the light blinks. Does this mean its time to change the filter, or do I change it when the light stays on even when not pouring?

Thanks.Pur water filter... when do I change it?The ligght would stay red when it's really time to change how ever I would go ahead and change now..........Pur water filter... when do I change it?About every three months.