Ever look at someones photos and they're plain terrible because it's blurry, out of focus or someones arm is cut off? There reason some people don't notice this is because they're in it and it holds a memory and gosh darn it... i like it. That doesn't fly well for me and other photographers. I'm going to explain how we look at a picture to determine if it's trash or worthy of being archived forever digitally or in print.
The first thing i look at when i'm looking through pictures is if it's sharp and the right things are in focus. The next thing i look at is feet, hands or arms & legs being chopped off in odd places. I look for people facial expressions as well as posture and exposure and basic content.
If i delete a photo i'm in basic terms nullifying it from any existence, as far as i'm concerned it never existed. I've never looked back and said i sure wish i had that blurry pic of Moses with his feet cut off and the focus was on the background and he was looking away. Think of it as cleaning house.
So no ones hands should ever be cut off or anything, if you're framing the picture for someones face then you can cut it off at the shoulders or around the neck. You can include their top half but make sure you include hands or something of a pose. If taking a picture of someone from head to toe, make sure it's head to toe.
So lets say the photo came out blurry but you love it, unless you have a dozen people saying that it's an amazing picture and they're not zombie liking a picture on facebook... get rid of it. I've taken a handful of pictures that classify as something classic, endearing or special in some way that have been blurry, out of focus or somewhat off but work. A photo doesn't have to always meet criteria to win approval or be a great picture, it's just often that it does. Thinks fries and ketchup, eggs and bacon, you can also do fries and gravy or caramel or eggs and jelly or eggs and ketchup; it may be a little off but still blows you away.
So get in the basic practice of importing your photos however you would like (I personally use Lightroom for my photo management) and start rooting through them. By doing this on a regular basis you will become a better photographer. By seeing the pictures that suck it will become obvious what doesn't suck and what areas you may need work on.
Your photography will improve as a result of giving bad photos the death sentence, you'll also save hard drive space by not keeping crap on your computer.