The ease or difficulty of re-flashing is dependent on the hardware. Some (most?) still need soldering, or at least a steady hand to hold wires in place, but the soldering on some things is far easier than others.
I've managed to flash half a dozen Sonoff light switches, as many power outlet switches, a whole bunch of Wemos D1 Minis, and even my kettle. Its generally straight forward and the first one is always the trickiest.
Initial OTA flashing might be a thing on some devices, but hasn't been on the Sonoff thing I have for a while. Once flashed though, you never need to touch the hardware again.
I've managed to flash half a dozen Sonoff light switches, as many power outlet switches, a whole bunch of Wemos D1 Minis, and even my kettle. Its generally straight forward and the first one is always the trickiest.
Initial OTA flashing might be a thing on some devices, but hasn't been on the Sonoff thing I have for a while. Once flashed though, you never need to touch the hardware again.
It's been a fun project or two.