Most visitors who come for work, family, or reporting spend their data in Kabul, with shorter hops to Herat, Mazar-i-Sharif, or Kandahar. Street-level 4G from Roshan, AWCC, and Salaam is a city thing; Hindu Kush valleys and district roads are not. Plan around towns you can actually call, not a cross-country loop that only exists on a paper map.
Cash is the Afghani (AFN). Cards fail at the first kebab stall, so you change money in Kabul and keep small notes for shared taxis that leave when the last seat fills. Friday is the weekly pause: ministries, many shops, and some bakeries go quiet. Eat kabuli pulao, mantu, and bolani with green tea, and learn a greeting in Dari or Pashto before you switch to English.
Hamid Karzai International is where the phone has to work — hotel pin, driver name, and a map that still loads when airport Wi-Fi does not. A travel eSIM covers the landing; a local prepaid SIM is an ID-counter errand if you stay longer. Coverage thins the moment you leave a provincial capital, so download offline maps while you still have a signal.