Its actually quite common with the teas we drink to often have a bag of tea that no longer has enough for an entire session, but still so many quality leaves that it shouldn't be thrown out. With some teas you have to get creative like blending leftover sencha's with other sencha's or Genmaicha just to use up those last bits. But certain teas (read higher oxidation/ higher roast teas) which can put up with a decent bit of air exposure, I realized could lend themselves to a bits and pieces jars. Now that I think about it I am not sure if the idea is completely my own, as I believe Jason said he had a jar of roasted oolongs that he mixed and matched just to use up at work. But that being said, to this jar I have been adding the ends of bags of Yancha, or adding some from bags of tea that do not seem that interesting themselves, or overly harsh themselves. There are upsides and downsides to this, but these mix and match jars once they get full enough, become a wonderful every day, or casual tea.
I am potentially considering using another Jar for Highfire Tie Guan Yin, although now that I have my 40ml Yixing, I brew incredibly small quantities at a time, meaning it would take a very long time to build up a critical mass of Roasted Tie Guan Yin. In terms of all the other teas I drink, the only other one I could consider putting together a jar of bits and pieces would be Hong Cha, as I do not think greener teas would stay fresh long enough to build up a critical mass.