Value of Tomica World boxes

Hi everyone,

Over the years I've amassed a limited  range of Tomica World and Plarail sets.

Sometimes the boxes have been thrown away (in the case of most trains) while some have been retained.

As I am more interested in the contents I am unsure about the value of the boxes themselves. Some are in decent condition while others are absolutely weathered (e.g. fading colours, rips, stickers). The worst ones are generally the sets that were purchased as used sets.

I know there are collectors of boxes and packaging; maybe some lurking around on these forums.

Can someone offer their opinion as to what are the most important factors in determining the value of the boxes?

Is it the printed content?
Is it the dimensions?
Is the quality?
Is the age?
What are the common deciding factors for the value?
Is there a rule of thumb to determine how much some of my boxes are worth (if I were to part with them)?

Thank you BPT!

-plarnold