> My current favorite business model is the "You're buying the current version and [years] of updates." Then typically you'll get some discount to renew your "[

> My current favorite business model is the "You're buying the current version and [years] of updates." Then typically you'll get some discount to renew your "[years] more of updates." Band in a Box has managed to make this model work for them for several decades now. Each version you buy does not expire, but only gets updates for about a year, and entitles you to an upgrade discount (slightly higher if you buy the next years' version, a little bit lower if you wait longer). The annual updates have both some new features and some new content, so there is always a bit of an incentive to upgrade, but no extreme pressure. Neither the software nor the business model are perfect, but both are reasonable enough to retain a loyal customer base.