Which dual lands should a Commander deck use?

Pain lands can produce colorless without damage or colored mana at a life cost. They enter untapped without asking for another land type, making them useful for early spells. They generally lack basic land types, so type-based ramp cannot find them.

Check lands enter untapped when you control one of the specified basic land types. Basics and typed nonbasics can enable them; a hand full of check lands cannot reliably enable itself. Evaluate the whole mana base before treating these as untapped sources.

Shock lands have two basic land types and can enter untapped if you pay two life. Those types make them useful targets for compatible fetch lands and ramp. Their value comes from this flexibility, rather than from being mandatory in every deck.

A fetch land searches for a land matching its stated types. Its color coverage depends on legal targets actually in your deck. Fetches can support landfall and shuffle effects, but adding one without useful targets is rarely your first budget upgrade.

A land that always enters tapped provides fixing at the cost of immediate mana. That can be acceptable for slower decks or tight budgets. Count how many appear in opening hands; replacing a few with untapped options can matter more than changing one basic to a premium land.