An always-on Raspberry Pi is a different workload from a Pi you switch on for an evening project. A server, a camera recorder, a home-automation hub, or a sensor logger writes small amounts of data all day, every day, and that steady writing is what wears a standard microSD card out. This guide is for anyone whose Pi never really sleeps.
Verdict up front: for an always-on Pi, buy a card from a named endurance line, such as the Samsung PRO Endurance line or the SanDisk Max Endurance line, in at least 32 GB and preferably 64 GB or larger. The endurance line matters more than the headline speed number, and a larger endurance card generally gives the controller more room to spread writes.
Win32 Disk Imager is Windows-only, version 1.0.0 from 2017-03-08, and its Read output is the full size of the device, with no compression. That matters for always-on Pis too: a backup image of a 64 GB card is a 64 GB file, so plan backup storage accordingly. The flashing workflow is covered in flashing Raspberry Pi OS with Win32 Disk Imager.
Why standard cards fail in always-on Pis
Flash memory wears out with writes. A standard card is designed for intermittent use: a camera writes a batch of photos, then rests. An always-on Pi does the opposite, writing logs, databases, or video segments continuously. Over months, that difference adds up, and the first symptom is often filesystem corruption, read errors, or a Pi that stops booting for no obvious reason.
Endurance lines address this by using flash and firmware tuned for continuous writing. This guide does not quote endurance ratings in terabytes or warranty years for named products, because those figures vary by capacity and by the manufacturer’s current specification sheet. Instead, compare product lines on the product page: look for the endurance designation, the capacity, and the intended use, such as surveillance or dashcam, and confirm the details there before you buy.
Comparison: endurance line versus standard line
| Feature | Standard line | Endurance line |
|---|---|---|
| Designed for | Cameras, phones, intermittent use | Continuous writing, 24/7 recorders |
| Best Pi use | Occasional desktop or learning Pi | Always-on server, camera, logger |
| Typical capacity advice | 32 GB to 64 GB | 64 GB or larger where budget allows |
| What to check | A-class, U3, V30 markings | Endurance designation plus A-class and V30 |
| Failure mode to watch | Gradual errors after heavy use | Still finite life, so backups remain essential |
For a current endurance line to start from, see this endurance microSD card on Amazon (Sponsored) — check the current price and confirm the endurance designation and capacity on the product page. See our affiliate disclosure for how sponsored links work on this site.
Sizing and setup tips for an always-on Pi
- Size up when you can: a larger card gives the controller more spare area to manage writes. For a recorder or logger, 64 GB is a sensible floor and 128 GB is worth considering.
- Reduce unnecessary writes: send logs to a remote server or a USB drive where practical, and avoid writing large temporary files to the card on every cycle.
- Keep a backup image: image the card while it is healthy. Our guide to backing up an SD card to an .img file shows the process, and restoring an .img backup to an SD card covers getting back up and running after a failure.
- Use a good power supply: brownouts corrupt cards faster than almost anything else. An official-style supply matched to your Pi model is cheap insurance.
- Test before deployment: a card that passes a full write test before it goes into service is far less likely to surprise you later. See testing a card with h2testw.
What to avoid
- Reusing an old phone card for a 24/7 recorder: a card that already served years in a phone has used up much of its write life before the Pi ever sees it.
- Choosing purely on speed class: a fast standard card is still a standard card. For continuous writing, the endurance designation is the deciding factor.
- Running with no backup: every card fails eventually. If the Pi holds data you cannot recreate, schedule regular image backups to a separate drive.
- Ignoring boot failures: if an always-on Pi stops booting, work through Raspberry Pi will not boot after flashing before assuming the board itself has failed.
You can find Win32 Disk Imager itself on our download page. For a Pi that is only used occasionally, the standard-card guidance in our best microSD card for Raspberry Pi guide is the better starting point.
Frequently asked questions
What makes an endurance card different from a standard card?
Endurance lines are designed for continuous writing, such as security cameras and always-on recorders. They are built to tolerate far more write cycles than standard cards, which is why they are the right choice for a Pi that writes logs, recordings, or sensor data around the clock.
Do I need an endurance card for a Pi I only use occasionally?
No. If the Pi runs for a few hours at a time and mostly reads data, a standard card with a good A-class rating is fine. Endurance cards pay off when the Pi writes continuously or runs 24 hours a day.
How long will an endurance card last?
That depends on how much data the Pi writes every day, the card capacity, and the workload. Larger capacities spread writes over more storage, which generally helps longevity, but no card lasts forever, so keep backups of anything important.