The repairable device: screws, not glue
What makes a phone or small device repairable: screws versus adhesive, pull-tab batteries, modular screens and ports, EU rules, repair scores and the honest trade-offs with thinness.
A repairable device is one you can open with a normal screwdriver, where the battery comes out without heat or solvent, and where the parts that break most often are separate pieces you can buy. That sounds obvious. It is also the opposite of how most thin phones, watches and earbuds have been built for the last decade, because glue is thinner, cheaper on the line and better at keeping water out.
We have spent this year drawing thin concept devices, starting with the Humanly Phone. Every time we shaved off a tenth of a millimetre, the question came back: what does this cost the person who has to fix it in three years? This post is our attempt to answer it properly. We are a software studio, not a hardware maker, so treat it as a careful reading of how devices are built, not a factory report.
Why most devices are glued
Adhesive solves several problems at once, and it is worth being fair to it before arguing against it.
First, height. A screw boss, the threaded post a screw goes into, needs material around it. A bracket that holds a battery in place needs its own thickness. A pressure-sensitive adhesive film can be a tenth of a millimetre or less. In a device where the whole stack is 5 or 6 mm, those fractions decide whether the battery fits.
Second, sealing. A display glued to a frame with a continuous bead of adhesive is also a gasket. That is a large part of how phones reach high water and dust ratings without extra rubber seals, which take space and can shift when dropped.
Third, the assembly line. Glue is fast to apply by machine, needs no torque control and adds no parts to the bill of materials. Screws mean more parts, more steps and more ways for a line worker to strip a thread.
None of that is a conspiracy. It is a pile of small, reasonable decisions that add up to a device you cannot open at your kitchen table. The cost only shows up later, and it lands on the owner.
Screws, tabs and connectors
Repairability is not one feature. It is a set of choices about how each part is held in, and how many other parts you have to disturb to reach it.
One kind of screw. The best-case device uses a single screw type and length throughout, with a common head such as Phillips or Torx. When a device mixes four lengths, putting a long screw into a short hole can punch through into the display or the board. One length means one driver and no map of where each screw went.
A battery on a pull tab. Batteries wear out first, so they matter most. The usual way to keep a glued battery serviceable is stretch-release adhesive: strips with a tab you pull slowly and at a low angle, and the adhesive lets go as it stretches. Some manufacturers have also used adhesive that releases when a small current is passed through it. Both are real improvements over a cell that has to be pried out with a card while it bends, which is how swollen and punctured batteries happen. Better still is a battery held by a bracket and one or two screws, or a cell in a rigid case with a connector, which is what a user-replaceable battery really means.
Parts on connectors, not solder. A USB-C port is plugged in and out thousands of times and collects lint. If it is soldered to the main board, a worn port means a new board. If it sits on a small daughter board with a flex cable and one screw, the repair costs a few euros. The same goes for buttons, speakers, microphones and the vibration motor.
Screen first or back first. Whichever side opens first should give access to the parts most likely to fail. Opening the screen side to reach the battery means risking the most expensive part to replace the cheapest. A back cover held by screws, with the battery right underneath, is the friendlier layout.
Parts pairing. Some manufacturers tie components to a specific device in software, so a genuine replacement screen or battery shows warnings or loses features unless it is authorised by the maker. There are security arguments for pairing biometric sensors. For batteries and screens the argument is much weaker, and it turns a screwdriver repair into a permission request.
What the EU rules are pushing toward
Regulation is moving in the direction of repair, especially in Europe. We are careful here, because the details are long, have exemptions and are still being interpreted. Read the official texts before making a product decision based on them.
The EU Batteries Regulation, adopted in 2023, includes a requirement that portable batteries in appliances be removable and replaceable by the end user, with the main obligations set to apply from early 2027. As we read it, there are exemptions, for example for some devices designed to work in wet conditions, and the definitions of "removable" and "commercially available tools" matter a great deal. How strictly it will apply to very thin, sealed devices is something we would not bet on yet.
Separately, EU ecodesign rules for smartphones and tablets that started applying in 2025 set requirements for spare parts availability over several years after a model is withdrawn, access to repair information, software updates and battery endurance. They also add a repairability class to the energy label shown at the point of sale. Our reading is that phones meeting a high battery endurance and water resistance bar can be exempt from the user-replaceable battery rule, which is one way manufacturers can keep a sealed design.
Whatever the final shape, the direction is clear. Makers are being asked to publish repair information, keep parts available and design so that the most common repairs are possible without special equipment.
Reading a repair score
There are a few kinds of repair score around. Teardown sites give devices a score out of ten after taking them apart. France introduced a repairability index for some product categories in 2021, and the EU label now carries its own repairability class for phones and tablets. They measure slightly different things, but most look at the same questions:
- How many steps and which tools it takes to reach the battery and the screen.
- Whether the fasteners are reusable, meaning screws and clips, or have to be destroyed, meaning glue and welds.
- Whether spare parts are sold, for how long and at what price relative to the device.
- Whether repair documentation is published, and whether software blocks replacement parts.
A high score does not mean a device is easy for everyone. It means a patient person with the right driver and a guide can do the common repairs. A low score usually means one step, often the battery or the display, needs heat, a suction cup and luck. When we look at a score, we skip the total and read the line for the battery. That is the repair almost everyone will need.
The trade-offs with thin and waterproof
It would be dishonest to pretend repairability is free. We covered the height budget of a thin device in Thin is a hardware problem, and screws eat into it.
A screwed back cover needs a gasket to stay water resistant. Gaskets take height, compress over time and need replacing when the device is opened. A device rated for immersion with a screwed back is possible, and some rugged phones do it, but they are rarely thin. A modular port board adds a connector, which adds height and another place for a fault. A battery in a rigid case gives up some capacity to the case walls, and in a small device that can be a noticeable share of the energy.
So there is a real choice, and different people should make it differently. A thick, rugged, fully modular phone is right for someone who works outdoors. A thin, sealed device with a stretch-release battery and good parts availability can be a reasonable compromise for someone who mostly wants it to survive the rain and be fixable once, when the battery is tired.
What we do not accept is the version where the device is glued for no reason other than cost, parts are not sold, and a tired battery at year three means a new phone.
What a thin, calm device could do
If we were drawing our phone concept again with repair as a first requirement, the exploded stack at the top of this post is roughly where we would land. It is not as thin as the original sketch. We think it is closer to right.
- Back opens first, held by four screws of one length, with a thin gasket. We would accept a splash rating instead of immersion to keep that gasket thin.
- The cell sits under the back cover on a single stretch-release strip with a long orange tab, plus a board-to-board connector. No prying.
- The screen is a module with one flex connector, removable after the mid-frame screws, so a cracked display does not mean touching the battery.
- USB-C, speaker and buttons on small boards of their own, each held by one screw.
- A published parts list and guide from day one, with no software pairing on the battery or screen.
A calm device helps here in a way we did not expect. When the phone does less, it needs less battery, fewer radios and less cooling, so there is a little room left to spend on screws and a gasket. The feature list and the repair list turn out to be the same budget.
If you build hardware and think our layout is naive, especially on sealing, we would like to hear why on the contact page. The gasket is the part we are least sure about, and it is the part that decides whether a screwed back ever gets past a drawing.