16x20 vs. 16x24 - which do you do/why?

Hmm, I'm a bit torn.

WHCC's price for 16x20s is $14.00. Their price for 16x24s is $20.50. Fairly significant difference, I was going to go with 16x24 but I'm not sure. People might rather have 16x20s anyway. Which do you use and why? I think I am going to offer 16x20.

The 16x20 format is a little more 'standard' and easier to find frames for, etc. But I would decide based on the content of the image more than standardization of size. If the image lends itself to a wider format then I would go with the 16x24.... such as a landscape where you want to see more and a wider format fits that content better. Now most portraits will look better in the 'stubbier' 16x20 format. But again, I would decide based on specific content.

Pick by photo content. What best suits the subject matter. Head and shoulder portrait is better 20x16, and standing portrait might be better in 24x16, a landscape might be best in 24x16, but an architectural photo might be better complemented by 20x16

Very good advice, thank you. If you are selling sports photos and want to make a price list for that how would you structure pricing (would you price the 16x24 the same as the 16x20?)