you mean that recurrences of warts don't occur over and over?
Recurrences aren't rare, but it is uncommon for them to keep happening over and over indefinitely. Usually, the immune system steps up and keeps this from happening. In some cases, though, frequent recurrences and stubborn warts do happen, and this might be seen more often, for example, in someone who smokes (smokers have a harder time clearing and remaining clear of warts), or perhaps is under great stress, doesn't get enough rest, is dealing with an illness, and so on.
Approximately 90% of HPV infections clear naturally in 6-24 months, though.
Hope this helps.