3 browsers?

You can have as many browsers you like

I have at least 3 browsers on computers. I have 4 on the one I'm currently typing this message on. This helps me if I have a problem with a website. I fire up another browser or perhaps 2 to see if the site works.

I have 4 also.chrome,edge,firefox and opera.

Chrome, Internet Explorer & Mozilla

I use Internet Explorer (current version is 11.0.200) and Mozilla Firefox (current version is 78.0.2) in Windows 7 and Windows 10.

I very much dislike Google Chrome and Microsoft Edge, so I doubt I will use either of them in the future.

As you can see from the replies so far, every one has their own browser preferences.

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Not only is it OK to have multiple browsers installed, but you can run them, independently and simultaneously, in separate windows without harm.

For instance, a website may not display some media content, or proper formatting in one browser, but will in another.

[edit]:
Browsers will ask you upon install or first use if you want IE, Chrome, Firefox, Edge or what ever - to be set as your default browser.
Say yes to the one you prefer.
You can change that at any time via the options/settings menus in any browser.