SD-cards ware out over time. So every now and then you need to check them. One of my Kodi media players, running on a Raspberry Pi, just died on me and refused to start at all. Flashed a new SD-card and it booted right away. Since I use a centralized database for my media players the time to fix this was minimum. Then I put the faulty card away with my other cards and of course mixed them up….
So I had to test them to figure out which one was broken. The easy way to do this is with H2testw that writes data to the whole card and then verifies it. But there are an additional step, at least if your main use of SD-card is for singel board computers like me. You need to clear them and make sure there is only one partition. I have mentioned my favorite tool for this in the past, SDformater. That is the official tool from SD Association so it would be safe to say that it’s the industry standard of doing this. Keep in mind that you need to use the “format size adjustment” option to clear all the partitions on the card. I’ve made a tool tip about SDformater before so please reference that for more information.
Then go ahead and download H2testw. It’s very easy to use, it starts out in Dutch (the small sub sea country in Europe) but have a toggle for English. Then just select the “target” (your SD-card drive letter) and select “write + verify”. The test takes a while depending on the speed and size of the card, it will fill the whole card with data and read it back again. This also gives you a good performance indicator for your SD-card.