If you've bought a computer for a particular reason, then I can help with your decision on what software to buy (or get for free). The most expensive program may not be the solution you seek, as many open source programs can fit the bill. You might be tempted to buy a suite of programs and they may be able to do everything you want, but not very well. New software is released every day and buying the latest could be an expensive path to take. I can advise you on the best and cheapest solution for your needs.
Even if you buy a brand new computer, the bundled software may not be appropriate. Many new PCs come with Anti-Virus software (an essential addition to any PC these days) but usually only a year's subscription. After that time, you need to pay to continue to get the protect it gives. Despite what manufacturers may say, free anti-virus software can do just as well and does not cost you anything. You are also not limited to how many PCs you can install the software on, an increasing trend with software solutions. Manufacturers often include custom software on their PCs which you will never need. A task I am often asked to do is strip off non essential software from a new PC.
Several of my clients have been reluctant to upgrade their PCs, saying that they are happy with the software and operating system they have. However, a fallback of this is the lack of support for the operating system, especially as you buy new hardware and there are no drivers for older operating systems.
Eventually there will be no support for older operating systems and if you want to get updates and better software, you will need to upgrade. Getting spare parts, like ink cartridges for old printers will become difficult as time goes by. The same can be said for updates for older versions of software. Manufacturers may give limited support for old versions of their programs, and when some smaller companies are bought out they may have no support at all. Companies may also have multiple versions of their software, a standard version, a pro version or an ultimate version. Chances are the software is the same, but the extras supplied differs.