You might think that the box size doesn't matter as long as the pieces can fit inside. But if you don't have a buttomless wallet of money it does matter a great deal.
Let me go through the different aspects that's affected by your choice of box size.
(a.k.a. "how many games of yours will be sold")
Getting the right spot on the shelves in a store can mean the difference between "being sold out" or "being overlooked".
You can compare it to Google Search results - it's all about being at the best spots where the most eyes look.
The example on the left is average store in Denmark. The frame indicate where you want your board game to stand. This was confirmed by the sales data I got from the store concerning some of the games (propably because I know the owners).
As you can also see on the picture - if your board game is too big or too difficult to handle it'll be place somewhere where it doesn't bother the setup (the floor or some high shelve where nobody can reach).
I measured some of the shelves in this store (they are standard equipment in most stores) and their average shelve height is about 28-30 cm. Which means that if you want to get a shelve spot your box shouldn't exceed 26-27 cm standing up.
Make sure that you take this into consideration so you avoid having to pay 3 or 4 dollars more for a package/delivery than you have to just because the box you choose is 1 cm too wide on one side.
Remember that for every dollar you spend on a single game you have to charge between 2 or 3 dollars more for the game in the end. More expensive games are harder to sell.
We all want to create unique products and therefore it might be tempting to also create an unique box. But in small numbers this is at least ten times as costly as going with a standard box size.
For my first game - this meant I had to resize my board from 50 x 50 cm to 48 x 48 cm so it could fit into a 24 x 24 cm box. Not a big deal and in the beginning this is easy money to save.
Other lessons learn
Remember that the lid of the box has to enclose the entire box! If the lid is not deep enough the result is that the box will tilt over if place in a upright position... and you don't want to irritate your customers nor the shop keepers out there ;)
If you like me have a game with content almost 2 kg heavy - you need a strong box - test it and test it again, it must not fail!
Until next time - Happy gaming :)