Why is it that a person catch so many colds in one year?

Many factors could be to blame. For example, it could be exposure to the cold viruses. If that is the case, what we are doing to prevent Covid from spreading would work for cold viruses=frequent hand washing, social distancing, masks. It could also be a deficiency in immunoglobulins-your doctor would be able to diagnose this by blood tests. Best of luck to you!

There are many viruses that cause a similar spectrum of symptoms, commonly called a cold. Infection with one type of virus does not provide protection against infection by a different virus. Many of these viruses keep mutating and infection with one strain may not protect against a different strain of the same virus.