Experience needed about butterfly clasp of Mk XII. and other bracelets

I would need reply from those who wear regularly IWC watches that use the friction-control (so no push-button) folding clasp bracelet regularly, that is open/close the clasp more or less daily since many years/decades. I'd like to know how durable the friction control mechanism is when regularly used for a long time, how many open/close manouvres can it take. I'm playing with the idea of buying a Mk. XII. but being a bracelet guy it is needed to know. Some other IWC models used the same butterfly clasp mechanism for their steel bracelets, a. o. some Da Vinci models, the meca-quartz Fliegerchrono, maybe others too. So the durability experience of the owners of the mentioned combos are also badly needed!
Thank you for any useful input!!!
Best regards,
Robert