Infection with many viruses will result in decades-long if not lifetime immunity, for example chicken pox.
Because of the large number of viruses responsible for the common cold, lifelong immunity to the common cold isn't possible; we will still be susceptible to those we haven't encountered before. But we do develop immunity to those we've been exposed to.
Influenza virus mutates quickly enough that there will nearly always be strains which will be new to us. Immunity to HIV is difficult because of the particular cells the virus attacks (as well as mutations).
However, Norovirus, while there are many strains, is particularly problematic because immunity to a strain lasts less than a year, making reinfection with the same strain repeatedly possible.
Is the reason Norovirus infection doesn't confer longer-lasting immunity known?