Its a matter of disconnect frequency , usage , and time. But at some point , which could be many , many years, you will probably need to replace one. It was about five years before I had to replace on the TS55 which was my most frequently used tool with lots of disconnecting.
It is suggested that you replace the cord and the tool socket. And check your other tool sockets for any signs of damage or wear. As for whatever reason the problem seems to be able to migrate. This has been pretty well discussed on FOG.
Also on the newer connections , at least in the USA, the amount of torque / force required to twist them fully into place can be quite high.