The hammock that most people picture when the word comes up is the wrong hammock. Two wooden sticks at the ends, a flat canvas slab strung between them, the whole thing hanging in the yard at a summer cottage. You climb in, the canvas folds you in half at the hips, your back curves into a banana, and after twenty minutes your spine is screaming. That object is responsible for the entire reputation hammocks have as a thing you nap in for half an hour and then quietly retire to the shed. Throw it away. It is the worst sleeping technology ever marketed under the hammock name.
The right hammock is the Mexican matrimonial, woven from thin cotton strings into a fine net, with a sleeping surface around four meters wide. No sticks, no spreader bars, just two end-loops gathered into a point, with thousands of fine threads fanning out between them into a lattice you could lose a fist in. When you lie in it the net spreads to take your shape. The width is the whole point. You sleep across it, diagonally, with your head at one end of the woven field and your feet at the other corner, so your body lies almost flat. The diagonal lay is the secret that the stick-hammock hides from you. With four meters of width, the diagonal is long enough that a tall adult lies straight, spine neutral, shoulders flat, hips uncompressed.
A matrimonial spreads pressure across the whole body. A mattress, even a good one, supports you at the shoulders and hips and ribs and forces the rest of your soft tissue to hang in between. The hammock supports every square centimeter of the body simultaneously, because the net deforms continuously around you. The contact pressure at any single point is a small fraction of what a mattress applies. People with bad backs and bad shoulders sleep in these things and wake up without the usual grinding. I have slept in matrimonial hammocks across four continents and the shoulder kink I used to fight every morning on a soft mattress has been gone for years.
Then there is the space. A bed, even a folding one, owns the room it sits in. The room is organized around it during the day whether you are sleeping or not. You walk around the bed. You step over the bed. The bed eats two square meters of floor and lives there permanently. A matrimonial hammock weighs about a kilogram and hangs from a carabiner clipped to a wall anchor on each side. Unclipping the carabiner takes a second. In the morning you reach up, pop the loop off, gather the whole sleeping system into a small bundle, and the room is empty. Floor space returns. The room becomes whatever you need that day, office or workshop or yoga floor or living room. At night the hammock comes back out and the room becomes a bedroom again. One room, two functions, zero compromise on either.
For people living in vehicles the math is even better. A bed in a van or a truck is a permanent platform that costs you roughly half of your interior volume. You either build over it or sit on it as a couch and call that a substitute for floor space. A hammock strung between two anchor points on opposite walls takes the same air that was already there. During the day you unclip it and the back of the vehicle becomes the full empty box it was designed to be. I have lived in a vehicle this way and the volume difference compared to friends with built-in beds is dramatic. Their dwelling is a bedroom with a kitchenette pinched into one end. Mine is a workshop that becomes a bedroom for eight hours a night and reverts to a workshop in the morning.
The one real downside is temperature. Your back is exposed to air with empty space underneath where a mattress would insulate. In cold weather that heat loss matters. The fix is easy. A wool blanket or a sheepskin laid into the hammock under your body solves it cleanly. The wool insulates the back while the diagonal lay still works the same way. In a heated room or a warm climate the cotton net by itself is enough. Below about fifteen degrees Celsius indoor temperature, lay something woolen under you and the problem disappears. Once you have done it twice the routine is automatic.
The other downsides people imagine mostly evaporate on contact. Two people fit in a matrimonial, hence the name; the width is genuinely enough for a couple to sleep diagonally in opposite directions without touching. Reading, eating breakfast in bed, working from the laptop in the morning all work fine, since the net adapts to whatever shape you sit in. Sex works, with a learning curve. The activities that need a hard flat surface still exist, and a hammock-room arrangement assumes you keep a yoga mat or a thin foam pad rolled in the corner for those.
Buying one is the part where most people get it wrong, because the market is full of decorative hammocks sold as the real thing. The matrimonial you want is hand-woven, four meters wide or more in the sleeping field, made of fine cotton, with thousands of threads in the weave where the cheap versions have hundreds. Cheap tourist versions sold in beach shops have a coarse weave that digs into the back, and a sleeping field of two meters that forces you back into the banana posture. The good ones come from the Yucatán and are sold by weight as much as by size. Expect to pay between forty and a hundred dollars from the cooperatives that still make them by hand. The investment buys you a sleeping system that lasts a decade and does for your back what every mattress fails to do.
Hang it correctly. The end-loops should sit at roughly chest-height when the bottom of the hammock sags about halfway between floor and hook. Pull it tight and the net cannot spread; leave it slack and you sit in a bag. The two anchor points should be far enough apart that the hammock keeps a gentle curve and stays unstrained. Forged wall hooks or carabiners through ceiling anchors both work; the load is your body weight times a multiplier from the angle, so the hardware needs a rating in the several hundred kilogram range even if you weigh seventy. Once the geometry is right, the diagonal lay falls into place automatically and the first night in it tells you everything the rest of this post has been arguing.
Most people sleeping on mattresses have never tried a real net hammock, and assume the experience would feel like the bad summer-cottage version. It feels like a different category of object, sold under the same name by accident of language. Spend a hundred dollars and two hours hanging it, and you find out within a week whether your back agrees with the rest of mine. Mine does completely, and I have slept in a hammock by preference for years.