First Patek — inquired a few months ago expecting quite a wait but got the call faster than anticipated. Weighs nothing, fits every strap type. Highly recommended for all considering the brand!
(It’s also nice having a watch that reminds me when it’s Wednesday, my dudes.)
Most of us never use it, but some professions use the number of the week all the time (I think accounting uses week numbers?).
In Denmark, it would be normal to ask "Hey, what are your plans during week 31, we might throw a barbeque?". I would find the function quite useful.