I’m sure all of you have seen those pull out sofa beds with bi-fold mattress that folds under the seating cushion. This type of sofa bed is notorious for feeling that bar hitting your back. The type of mattress used is about 5” inches and tends to be on the flimsy side.
If you have limited space, which most people in apartments do, a convertible sofa bed with the mattress being part of the frame, will provide better comfort and save a lot more space. Keep in mind that the popular pull out sofa beds need at least 88” of clearance from the back of the frame to the end of the mattress when open, regardless of the size, be it twin, full, or queen. This tends to take up a lot of space, leaving very little room to walk around the sofa bed when opened. Also, you have to remove all those seat and back cushions which also take up a lot of space.
There are a few solutions on the market for convertible sofa beds also referred to as click clack sofa beds, that are very small in width, and are comfortable to sleep two people.
All of these convertible loveseat sofa beds are under 70” wide and open to less than 78” long in the bed position: