It’s physically impossible to attend every university that does the course you want to study. So you’ll need to narrow your choices down.
You can do this by researching the location of each university. Could you see yourself living there? Is there a good social scene? Do you want to be far from home? You will also need to look at the individual differences between each course. Do some offer work placements? Have some got modules that interest you more than others? Finally, you need to research the university itself. Has it got a good reputation? How many graduates are employed in their chosen field?
Once you have looked at all of these aspects, you can decide which universities are most suited to you. There’s no rule as to how many open days you should go to but the average is around 4 or 5. This doesn’t mean that you’re not normal if you only decide to visit two. It’s just that some people like to have a wider range of options or find it difficult to narrow their choices down.
Some people are studying at a university that they never went to visit and don’t regret choosing it. Others pick their top university choice on the basis of the open day. Open days can stop you from choosing a university that you might not have enjoyed and they can confirm your thoughts about a particular university or course.
It doesn’t matter how many open days you go to. The vital thing is that you choose the right university and course for you. If that means that you want to go to 10 open days, go for it. If you only want to go to a couple, that’s alright too.