I was surprised to notice that I was using way more credits in the Keyword Explorer than expected. This happened because I switched between the Overview and Keyword Ideas. As confirmed by your support, I have to pay a credit every time I open the Keyword Overview.
I would like to have a way to force the display of cached results. I think that this behavior might be unexpected from a user interaction standpoint; most people probably don't need the (paid) refresh after a few minutes but there's currently no way around it.