Organizations switching from a perpetual license model to a subscription-based one will have to adjust to the concept of software expiration. While there's plenty of justification for leasing company vehicles rather than buying outright, leasing software -- particularly online software -- is a much trickier sell in our book. However, we suppose there's something to be said for quarterly updates to product features and regular virus definition updates; server maintenance, availability and backup; and Web and phone support 24x7. Just don't forget to pay that bill. Because online Office 365 files become read-only if the subscription lapses. How's that for leverage?