Long time beancount+fava user here. To answer your question Re Cash: Note I may have a different definition of cash. In my ledger, cash is anything that I can

Long time beancount+fava user here. To answer your question Re Cash: Note I may have a different definition of cash. In my ledger, cash is anything that I can liquidate in <1 days. That includes saving/checking/CD. As for your question about the real cash in your wallet, I tend to not account for those. Re Interest: Interest should be correctly recorded. That means the interest for your checking/saving/CD should be recorded, as well as clearly separate your loan payment into two legs (principle and interest).