I'm considering a redesign involving moving from maintenance-unfriendly mezzanine connectors for daughter cards to a real backplane with card edge connectors.
I like how easy and physically robust card edge connectors are. I'm a bit worried about reliability, though.
My environment should be generally sealed, but with high temperature cycling. (inside a NEMA 4 enclosure, but located anywhere from hot deserts to frozen tundras)
I've read that a thicker gold plating on the gold fingers isn't that much more expensive and adds considerable life. Is that good enough? These units need to live in the field for a long time. (10+ years)
How about upgrades? Can I expect to be able to leave a unit in the field for years and then install an expansion card in a slot that's been unused that long? How about when replacing a card with another one?