There is no definitive answer to this question, as it depends on the blog’s specific needs. However, a general guideline would be to have at least two to three plugins.
This will give you the ability to customize your blog’s look and feel, as well as add additional functionality.
If you are just starting out, it may be helpful to start with one plugin and see how it works before adding more. Additionally, some plugins may require other plugins in order to work properly, so it is important to check ahead.
Ultimately, the number of plugins on your blog will be a personal preference and will depend on your specific needs.