Literally just posted today looking for information about a replacement headband. Had them about three years and treated them well. They still broke. It is a very real possibility even if they are taken care of.

Take a look at this thread for a look inside the headband and some discussion on why it's a common problem:

https://www.reddit.com/r/headphones/comments/s8wo4x/why_focal_headbands_break/

They do sound great though.