The mistakes that cost money three years from now are made in your first three months — in contracts you sign without knowing the German rules. None of this takes long, and all of it is easier before you settle in.
Which mobile plan actually fits your tour? — Five questions, then an honest answer about data, contract type and a fair price. You walk into a shop and get offered twenty-four months, because they ask what you want rather than how long you are staying.
Broadcasting fee — You are exempt under the Status of Forces Agreement — but only if you apply. €18.36 a month lands on every household in Germany.
Do not land in the default electricity tariff — Doing nothing when you move in puts you in the most expensive tariff there is. Move in and say nothing, and you are automatically supplied under Grundversorgung — reliably around a third above market.
Which minimum term is safe for your tour? — A term is not bad because it is long. It is bad because it outlasts you. Twenty-four months on a three-year tour is fine.
Which VAT form for which purchase? — Get it wrong and the tax relief is gone — there is no fixing it afterwards. The €2,500 line is measured on the net price, not on what you hand over.
Provider directory — Who the German providers are, where they sit, and how each one has to be contacted.