Sometimes it's the little things that make the world of difference, and that's true of photography too.
I went through three phases of buying accessories for my camera. First, I was convinced I'd uncover something revolutionary and I bought everything I liked the look of. Then, phase two was realizing that pretty much nothing I had bought was of any real use so I spent years not buying any accessories at all. Now, I'm in phase three which is where I spend a long time deliberating and researching these small purchases. Since being in my frugal and sensible phase I have made a few purchases that have really paid off.
I won't name any that feature on this list, although the quick release plate was certainly a great move. For me, the best accessory I've ever bought for my camera was folding tilt plate for my tripod, sometimes called a Z plate.
If you do macro work in particular, this can be incredibly useful for making adjustments to the angle of the lens, or for macro stacking. I bought mine a few years back and it is a staple for my product photography in particular.
What's the best camera accessory you've ever bought? Share your thoughts in the comment section below.