People often know they need a longer lens but don’t know just how long is long enough, or need a wider lens but have no idea if the extra 2mm on the wide end of the 14-24mm are worth $550 more than the 16-35mm.
Nikon’s lens simulator is a great resource for anyone debating which focal length they need or how various focal lengths compare to each other.
The simulator starts at 14mm and zooms all the way in to 800mm for FX format lenses and 10mm to 300mm for DX lenses, showing the resulting angle of view at any given time.
Camera wise you can select between FX (full frame), DX (APS-C) and CX (mirrorless) format models, going back about 6 years and up until Nikon’s newest models.
This simulator can be just as helpful for Canon, Sony, Olympus and any other brand users. All you have to do is take into account the slightly different crop factor.