We recently finished a series of four shooting courses here at Light and there is one piece of gear that is consistently needed. Regardless of subject, technique, camera, etc. the HoodLoupe is a must have.
I did a video last summer regarding the HL ( HoodLoupe Video ) and every shooting session reconfirms.
There is such critical information available to us on the LCD whether in Live View before the shot or when reviewing images/histograms after the shot; try not to pass it up. The loupe will help you eliminate distractions and overcome bright lighting conditions to focus on the LCD.
As you know, I am always a full disclosure guy. Hoodman does not compensate me for endorsing their gear. It is just the best stuff out there.
If you do not have one yet, just do it.