>> Also good to have a strategy for currency conversions on a cheat sheet.

That is easy for you 1 AUD = 100 JPY

I just found out on my last trip abroad, returning last week from London, Berlin and Istanbul, that the iPhone calculator now has a new currency calculator built in. There are probably all the currencies that you will ever need listed. I can do Euro- dollar, Pound -dollar and Japanese -dollar in my head but Turkish lira-dollar makes me pause.

I use the Suica card as my Japanese IC but you can put it on Apple pay. My card is rather old and I still use it but I have been slowly moving everything to Apple pay. It is apparently more secure than using a credit card according to a friend of mine who is a Google engineer who works on Google pay. Last year I had trouble transferring money from VISA to my Suica card online but my AMX card worked fine.
I should also add that my daughters love to shop at Don Quixote which is a large discount store. There is a Mega one in Shibuya.
There are also many other Convenient store in Japan such as Lawson and Seven- Eleven.

Not only currency, but it has all sorts of useful conversions -- temperature, weight, distance, speed, etc.

I just told Siri "Convert 1 dollar to Japanese yen" and my iphone showed it was 156.04 yen. Told my TV "dollar yen rate" and it gave an audible response of 156 displayed 156.07.

Told Siri "Convert 1 dollar to Turkish lira" and it replied TRY 35.17, both audible and visual. It actually said "35 lira and 17 kurus". Google says 35.19.

dollar meaning USD

If their phones let them add the Suica card directly to their Apple Wallets, that's the most convenient way to handle metro fare. It's so convenient to just tap your phone on the entry and exit gates rather than having to pull out a separate card or use a paper ticket. It's also super quick and easy to add money to the card balance.

Also, IMO the quality of Japanese conbinis are ranked as follows: 7-11, Lawson's, Family Mart (but all have more-than-decent food).