Yes, I expect we will see a new mug design by March 2013. By early 2013, the current design will be in rotation for two years and will be due for a change. Well the lids help with accidental spills and they do pretty well when mostly upright. But they are not liquid-tight because of the rotating drink-hole cover. If a mug ends up on its side or upside down, it will leak. I wouldn't put a mug with any drink inside into a bag; you'd need to keep it out.