Isn't that just what insurance is though? We did the same thing a couple years back after a supplier screwup and kept the retainer for six months. Never used it once. What made it worth it was having the firm's number already in our contacts with a plan on file, so when a small thing did pop up we were not scrambling at 11pm writing our own statement. If the money is gone either way, I would rather have the bench sitting there than not. Just don't let it renew on autopilot if cash is tight.