Full beds were originally made to accommodate couples, which is why they are often called
double beds. Until after World War II,
full size beds were the largest bed size commonly manufactured. Today, couples typically sleep in larger beds and
full size bed frames are more commonly used by one person.
Full bed frames use the standard full size mattress dimensions of 53" x 75". A
full bed in your spare guest bedroom is a great option.
Double size beds are small enough to leave some floor space for everyday use yet can accommodate couples as overnight guests.
You might also consider
full trundle beds,
full headboards or
full bedroom sets.