well i am not a jeweler, i am in IT and we say if its not broken, dont touch it...
my little brain tells me constantly doing/undoing the lock would increase the chance of it being broken.
but when they told me i cannot sleep or shower with my dbty and therefore i will have to pay for the lock repair, and when i suggested it should deteriorate the lock less if you dont use it at least twice a day, the customer service lady smiled nicely and said tiffany does not recommend sleeping or showering with your jewelery as the hair can get caught in the lock etc etc etc and therefore since i admitted to it, pls pay!
i did not mind the paying bit since i was extending it anyway, but i personally believe for me its safer to leave this type of necklace on.
i was VERY annoyed the lock broke and left my dbty on a floor, which i noticed/saw only by a chance. i also asked for a "better" or "safer" lock to be fitted and i was told there is only one type which i have and therefore no other lock can be fitted by tiffany.
can u tell i have a luv and hate relationship with tiffany?
good luck with your search. i sese some posts here looking for 24x7 necklaces...its exactly what i am doing now, searching for dbty replacement as my tiffany dbty is going!!! i went to costco today, not much physical activity really.. and when i got back and checked the mirror, my beautiful and sparkly .25 stone was exactly in the middle of my back, right opposite where i would like it. instead i saw my repaired lock!