Besides shelling out for , users should expect to pay for Vista upgrades for many of their favorite Windows software.

Rather than releasing free patches to update existing versions, leading vendors such as Adobe Systems Inc., Symantec Corp. and Intuit Inc. are choosing to add Vista compatibility only to new releases or still-in-development future products. Most of these new versions will add significant features along with Vista compatibility. And, vendors will argue, if Vista compatibility is a new feature, what's unfair about packaging a new feature only in new versions of their software, rather than going back and patching aging versions nearing the end of their product life cycle?

Still, many customers who are happy with their existing software may look askance at what they consider less-than-subtle attempts to coerce them to upgrade. And that, according to analysts, could rebound on Microsoft as well as Windows software vendors by prompting users to hold off Vista upgrades or consider switching to another operating system altogether.

Technical shift from XP to Vista seen as 'incremental'

How software vendors handle transitions for operating systems has long been a delicate, high-stakes issue. Move to a new platform too slowly, and you risk ending up like Lotus Software's 1-2-3, the dominant spreadsheet on DOS in the late 1980s that lost its lead to Microsoft Excel in part because it was belatedly ported to Windows.