Is there any trick to getting these stickers to last longer than a few months?
Got to keep it out of the weather/sun. Put the map on your slide maybe
Some stickers are more resistant to UV than others.
Kind of a gamble with these map ones. We got a license plate themed one from Amazon. 2 years of full time and faces the sun a lot.
Colors are still in good shape.
Try a different brand is the only advice I can give.
Edit: the one we got is Lushleaf Designs RV State Map. Specifically says UV resistant. They say they use 3M UV resist sticker material.
Source: Sticker