I've been a Prime member for about five or six years, and for a while I shopped there the same way you did (sat down and spent time on a "shopping trip" to pile

I've been a Prime member for about five or six years, and for a while I shopped there the same way you did (sat down and spent time on a "shopping trip" to pile up the cart to make it "worth it"). The tipping point for me was in early '09 or so when Amazon introduced their iPhone app. At that point if it came to my mind that there was something I needed, I'd just pull out the phone and buy it immediately on Amazon. That changed my habits too when browsing their normal desktop site. From then on, the vast majority of my Amazon purchases have been one-off purchases where I knew what I wanted, spent two or three minutes searching, bought it, and got out. And I do it often; between me and my wife's purchases there's an Amazon box on the front doorstep 2-3 times a week.