Ulaanbaatar "suburbs"

From a hilltop North of the city, you can see the sudden transition from 21st century skyscrapers to 13th century gers (felt tents).
40% of the residents of Ulaanbaatar (UB), (400,000 people) live in gers surrounding and within the city.  No plumbing, refrigeration or solid walls.  It gets to -40F every winter.

No checks or credit cards accepted

So if you need to pay a big bill in the countryside, you can't use a check or credit card.  The largest bill in Mongolia is a 20,000 Tugrik bill worth about $17.00.  So you need to take a LOT of bills.  Try finding a wallet that can carry this.  Of course, inside your del (Mongolian traditional robe) no one would notice, except to say,"You've gained a few pounds!"  Clever Mongolians.