As all good Yankees know, aside from that goofy one dollar coin that no one uses and is dispensed almost solely by Boston area subway ticket machines, the highest denomination coin is the good 'ol 25 cent piece.
If you are anything like me, you probably get rid of quarters by pumping them into vending machines or tossing them in the tip jar. Basically, quarters and miscellaneous small change don't feel particularly consequential when spending them. Unfortunately, many people (myself included) have carried this wasteful attitude across the waters to Japan. In a country with nearly as meany vending machines as people, I have found myself throwing away one hundred yen piece and five hundred yen pieces with reckless abandon normally reserved for small change.
This leads me to this week's pro saving tip for recent arrivals...If you are prone to buying things on a whim (i.e. vending machines), then try to break the habit of trivializing small change or at least stash it away somewhere for a rainy day. You would be shocked at how easy it is to waste several thousand yen a month without realizing. This is especially true if your daily commute takes you through any area with lots of vending machines and convenience stores.
If you have poor self control, try getting a coin bank from your local 100 yen shop. If you count up your coins every month then you might just be shocked at how much you end up saving!