In case you still have questions, take a look at the LEDE forum: https://forum.openwrt.org/c/hardware-questions-and-recommendations.
Flash devices can be written to, at minimum, anywhere between 100,000 and 1,000,000 times (according to the manufacturers). Keep in mind we have a normal distribution and also, that Flash never ever just stops working, but merely distinct blocks do. I.e. you won't be able to write to them any longer, but you should be able to still read them.
For details see Flash memory
→ Quick Start Guide - Installing OpenWrt should hook you up.
A release build of OpenWrt is a stable version of the firmware. It is expected to be supported for the long term, and is safe to use in production, or with your family.
A trunk (or snapshot) build is a version of OpenWrt that is “in development”. These are rebuilt frequently, often multiple times a day. Although they are the latest version, there is no guarantee that any particular snapshot build will be bug-free, or even work at all.
See also Development builds / snapshots
The two have the same content, but a factory image would have extra header information or whatever the platform needs. Generally speaking, the factory image is to be used with the OEM GUI or OEM flashing utilities to convert the device to OpenWrt. After that, use the sysupgrade images.
CONFIG_ALL=y + make V=99 IGNORE_ERRORS=m
When trying to install a firmware image, I get the following error:
Error code: 18005, Upgrade unsuccessfully because the version of the upgraded file was incorrect. Please check the file name.
Solution: Rename the firmware image to something short, like e.g.