I currently have the Superfeet blue insoles in my La Sportiva hiking boots. How do I know when it's time to replace the insoles? I've had them for 1 year and hiked about 400 miles so far. Both the boots and insoles were new. But I recently started getting blisters on my big toe and heel. I haven't changed socks or my hiking style and this is happening on trails I've hiked previously.