Cartagena rewards people who ask questions before spending.

Before renting or booking:

Check AC in bedrooms, not just “has AC.”
Ask about electricity costs.
Check nighttime noise.
Confirm water pressure.
Ask about building rules.
Check walking distance in heat, not on a map.
Confirm taxi/app access.
Ask whether prices are local or tourist-zone prices.

For beaches and islands:

Do not compare Bocagrande beach with the Rosario Islands.
Research the exact island, beach club, or operator.
Bring cash.
Confirm what is included.
Ask about boat times and sea conditions.
Use firm but polite “no, gracias” with vendors.

Cartagena is much better when you stop expecting every day to feel like a postcard.