I am paying for two accounts and have a third with Shell, paid by my MF's to Shell. My two II accounts ended up being a necessity because I decided not to continue to add the kids to all of our deeds, so the last five years or so of purchases are just in our names, so that the kids don't have to take those at some point (after we die).
For a while, II was letting me deposit my weeks without any kind of issue. For example, Vistana, we own quite a few weeks, some in the kids' names, others in just our names. II started rejecting my deposits last year, so I was literally stuck with a bunch of weeks I had to deposit somewhere, so I opened a second account.
II also stopped me from depositing my Blue Ridge Village (same reason) and my Marriott's Willow Ridge. When we opened our second account with II last year, I had to add all of those units into the system, so they wouldn't charge for each one later. It took a lot of time to do it, but I am glad I got it done. I also added platinum with a code I got in the mail and posted here on TUG for all to use. That was a good deal for me because I like the platinum benefit. I can add the kids without paying a GC fee. Our older account, I was never charged a fee for adding them, but this 2nd account being in just our names, with the timeshares just in our names, it was necessary to add that Platinum benefit. It paid for itself back in one trip with our son and daughter-in-law because they are staying at Westin Ka'anpali Resort (not north) for two weeks.