The recent release of Windows Vista, and the controversy surrounding it, has sharpened focus once again on the perennial question of just when is the right time to upgrade software, whether it’s on your machine or the machines of those in your department or company.

Windows Vista, the newest version of the most popular personal computer operating system on the planet, was under development for years. The time between its release and that of its predecessor, Windows XP, was more than 5 years, the longest ever between Windows versions. The program was tested extensively, both inside Microsoft and by outside volunteer beta testers. The computer magazine reviews were largely positive.

Yet since its release, reports have surfaced about compatibility problems in using Vista with existing software programs and hardware peripherals. Some people who have upgraded have since “downgraded” back to Windows XP. Others buying new computers have asked hardware vendors to include XP instead of the “new and improved” Vista, and many vendors have complied, making XP an option on some or all of their systems.

The problems surrounding Vista are hardly unique. The open architecture of PCs, with many thousands of different companies making computers, software, printers and other peripherals, and software drivers to connect peripherals to computers, means there are and always have been countless avenues for incompatibility glitches.

One of the oldest, most common, and wisest pieces of advice in deciding to upgrade any software, whether it’s an all-encompassing package such as an operating system or a group of smaller but still critical applications such as an office suite, is to wait until the first set of bug fixes is out before migrating to a major upgrade.

Microsoft is working hard on Windows Vista Service Pack 1, which is scheduled to be released sometime before the end of the year. Along with fixing many of those thorny incompatibility glitches, the service pack will include performance enhancements and added flexibility such as the ability to run your choice of desktop search programs, including Google Desktop, as the default rather than the search program Microsoft provides.

Many users experienced no compatibility glitches with Vista, according to anecdotal reports, which is the case with most software upgrades. Upgrading is typically a fun, even exciting, activity. Buying and installing a software upgrade can be like taking the wrapping off of a gift and seeing just the present you were hoping for, with new computing tools that are enjoyable to use while, at the same time, making you more productive.

You don’t have to be a computer geek to enjoy software upgrades, though it can help. At the opposite extreme, some computer users get stuck in their ways, holding onto old software, even while upgrading hardware, because it’s a known commodity, comfortable, and works well enough. This typically happens to technophobes, those who actively dislike or just tolerate computing as a work or school necessity.

On the other hand, some former geeks turn into phobes, just as puppies turn into old dogs, refusing to learn new tricks, even when the tricks would make their work or personal lives more productive or enjoyable. Some people out there, even entire offices, are still running WordPerfect 5.1 for DOS, a program that was released 18 years ago.

There’s something to be said for the maxim, “If it ain’t broke, don’t fix it.” But this should be a decision-making process, not a knee-jerk resistance to change.

In deciding whether to upgrade any software program, you should do a formal or informal cost-benefit analysis, say experts. At a minimum, it should involve these five steps:

1. Learn what’s new out there and what benefits it promises.

2. Tap into the collective wisdom of how well it delivers on its promises by reading reviews and seeking out opinions of peers in online discussion groups, consumer evaluation Web sites, and blogs and offline through discussions with those whose expertise you trust.

3. Gauge the difference between the benefits of the new and what you already have.

4. Tally the costs to upgrade, including the price of the software, the time it takes to install it, the likelihood of glitches, the need for training, and whether hardware should also be upgraded to better match the software.

5. Determine whether and when you’ll be losing technical support for your old software. Software companies are increasingly discontinuing support for older products, to cut their costs and to motivate users to buy upgrades. If you rely on that support, you may not have a choice.