You must take the time to protect yourself. If you do not, you could easily lose your identity. Or your bank or stock market account could be raided.
Fortunately, the threats are generally well understood. Protecting yourself is not difficult, although you may have to travel a learning curve.
The information that follows is written for the owners of Windows machines. There have been no successful attacks on Apple's Macintosh computers, to my knowledge. Why?
Apple believes its operating system--OS X--is inherently more secure than Windows. That may be. However, Apple has released many, many security fixes.
The bigger reason, I believe, is Apple's smaller market share. Criminals are looking to make money. Apple has a tiny slice of the computer market. Windows has over 90 percent. It makes a much juicier target.