There are a number of steps you can take to help determine if an unfamiliar utility is safe.
When Microsoft stops support for XP your computer will keep working. The big problem is unsupported vulnerabilities.
Lots of people keep their passwords and sensitive information in documents or spreadsheets sporting a password. Is that really safe?
Printer drivers are not always made for Linux distributions. But there are a few alternate roads you may go down to use your printer.
A cluttered desktop doesn’t slow down your computer in and of itself. But this could be a symptom of deeper problems.
Current versions will continue to work. The real problem is what happens with future versions.