Don’t leave a pump too long without being rotated. You could find:
The seals fuse together or onto the shaft, so it leaks when you do eventually run it
There’s a problem with the pump that you weren’t aware of, so when you come to need it the pump isn’t usable
Matter builds up in the impeller volute and on the stationary impeller, causing the pump to seize
Bacteria builds up in the water in the pump and pipework, causing infections such as Legionella in potable water
It’s well worth running every pump for at least a few minutes once a week to avoid these issues, along with checking the valves as on the previous update.
Also, if your pumps are similar to the ones in the photo, you would be well advised to consider replacing them with a modern twinhead pump. This will remove the problem of bacteria building up in the dead leg on the standby side, and be a much more reliable system. And not only that, within 1-2 years you’re likely to have got your money back on the pumps and be saving money, because they’re so much more energy efficient.