Using a Safe Deposit Box for Key Storage

I recently visited my bank, and they mentioned I could have a safe deposit box set up with the option to keep it locked for as long as I want! A large enough container that can hold dozens of keys costs just $15 annually, which seems ideal for people like me who don’t use traditional keyholders. Now I only need to convince myself to spend hundreds on a polished CB. The worry is that I might make a rash decision and ask them to lock it up for half a year or so!