I am constantly asked why I shoot in Aperture Priority mode. I figured I'd explain what Aperture Priority mode is and why it's the way I have been shooting for over 5 years now.
Every time you take a picture there are three main adjustments you have to worry about: The ISO, Aperture, and Shutter Speed. By default, Aperture Priority mode set the shutter speed and ISO automatically based on the Aperture you set. Typically I'm looking to capture an image with as little noise as possible so I like to manually set my ISO to 100. Now that I only have the Aperture to worry about, I ask myself: "What kind of depth of field am I looking to get out of this image?" If I'm taking a landscape shot, I might want a higher F-Stop. If I want to blur the background behind an object, I might want a lower F-Stop. Once I set the Aperture I press the shutter and take my photo.
There are occasions where you're shutter speed is too slow and causes the image/object to blur. This can easily happen in dim lighting / at night, if you are holding your camera instead of using a tripod, or if there is a moving object you are trying to capture. If you want a faster shutter speed, increase the ISO until you're happy with the result. I know... I know... Increasing the ISO increases noise. However, if you want a specific Depth of Field, the only way to make your Shutter Speed faster is by increasing the ISO, but don't worry! Cameras and software now-a-days are so advanced, noise is easy to remove/decrease.
My camera is set to Aperture Priority mode 95% of the time. I only switch to manual mode if I am using a ND filter and my camera doesn't set the shutter speed correctly.
For some reason a lot of people act like shooting in manual makes their photos better. I set my camera based on what I need and what I need is as little noise as possible (ISO 100) and a certain Depth of Field. I don't care what the shutter speed is as long as it captures what I want so why not let that be set automatically?
I love shooting landscape photography which is why I stick with Aperture Priority, but I'm sure other photographers have different opinions based on what they shoot. I'd love to hear the way you shoot and why it works for you. I may learn something I have never tried before.