When it comes to stickers and signs, the resolution needed of your bitmap image will depend how your sticker or sign is to be viewed.
Big signs generally have a lower print resolution as the viewing distance starts from a few metres away which means any fine detail wouldn't been seen, economically it is not worth producing something that no one will see. Lower resolution files are easier to manage and have a smaller file size.
Small stickers and labels will generally need a higher resolution because they will contain elements that will be viewed just a few centimeters away.
If you are unsure about your artwork you are welcome to send it to us and we can advise what can be done with it.