I rebuilt my disconnect. New bearings and seals. Took more time but cost less than replacing the whole thing. Granted I broke my housing and had to get one from a junker so that drove the cost back up, but normally it is only around $60 for a set of new parts and the time to put it together.
If you let it go too long it can wear down into the housing and require replacement, and/or result in the internal shift fork breaking when trying to engage it with it so misaligned. Just adds more cost to the rebuild. The easier route is just to pony up for a whole new disconnect assembly.
The fun part either way is the housing fits so tight to the oil pan that sometimes it won't come free and instead breaks off. Then you get to extract the broken bits without damaging the oil pan. It isn't a terrible job, just takes time as you have to be careful. Not all of them seize up. Mine did though, of course... I put anti seize on the collar of the newly rebuilt one where it fits into the side of the pan in case I ever had to take it back apart. Thankfully I never did (partially because I used a far superior grease inside, I suspect).