I seem to have a recurring issue with MOSFETS.
I'll make something up on a breadboard, it works, then build the project and solder everything together. Then at some point (not always immediately) my MOSFETs, rather than switching off with a gate voltage of 0, seem to continue to conduct current (just as if its a 50hm resistor). I'm using N channel devices with the Source to Ground, so the right way round.
I guess i'm some how killing them, but have no idea why any suggestions ?