Internet can be addicting for some people. i don’t think it’s any sign of mental illness.
Also depends on what you are looking at…I tend to do productive stuff as opposed to games, pornography and gambling that some people spend hours on
I go on a couple forums, email with a very few people with meaningful conversations, as it is really my only contact with anyone. I look at news, do research into various topics, get my spiritual fellowship. Occasionally watch a youtube video : music, or short vids about interesting topics usually dealing with spirituality, nature, and maybe quantum physics…
I don’t have TV or radio. I do spend some hours online but it’s broken up between working around the house. Several years ago when i worked online i would spend up to 16 hours a day on the computer…but had to in order to watch investments and be ready if things looked shaky…so that was technically 'work"
So it really depends what sites you are going to. this particular forum I think is good because it’s a form of fellowship, even therapy for some, and you can offer advice and get advice.