Be aware that in many older ships, elevators will probably not operate to the lower-most decks. Some even have a whirlpool bath and bidet, a hair dryer and more space. Two beds or a lower and upper bed or a double, queen or king size bed. In some ships, twin beds can be pushed together to form a double. Some smaller cabins have bunk type beds with a ladder to access the top bunk.
Many brochures list the type of bed for each cabin shown.
Double beds are more common on the newer ships in the higher category. Depending on cabin size, a chair, or chair and table, or sofa and table, or even a separate lounge or sitting area. Closet space, some drawer space, plus storage room under beds for suitcases. Bedside night stand. Towels, soap, shampoo and conditioner.