Mating expected life is generally in the data sheet for a connector.
And if TEco actually released actual datasheets, that'd be wonderful...
ovnr, regarding durability, do you have any words?
Since they will be used in a prototyping platform they may be mated/unmated several times (~100 at least) without compromising the quality of the connection.
Are you aware of the differences between the fine-stack and fine-mate series? They seem identical, but the last one is more expensive so it should have some "special sauce". (actually they do not seem identical)
Durability: Never used these exact ones myself. If you're careful it should be fine, but if you have the option I'd strongly suggest making a cable for the prototyping - just make up a board with connector footprints and a FFC connector, then slap that on between them - easy peasy probing and fiddling.
And no, the Fine Stack and Fine Mate series are not compatible.
Edit: Sorry, didn't read your post properly. If you're making a product where the "end user" (be that actual lusers or hobbyists or whatever) will be plugging and unplugging all day long (as opposed to people who know what they're doing), you'll need to pay a lot more attention to what parts you're using. I'd probably end up buying a few different connectors and doing a lot of testing.