Dear Ms Wise, we’ve been with the same health fund for about 25 years and were stunned to find recently that my wife is not covered for her double knee replacement. The problem is that about seven years ago, someone from the health fund suggested that since we no longer needed cover for obstetrics etc (we’re in our late 60s), we could get cheaper cover by changing our options. We did this, happy to be saving money. I notice some funds are offering a six-month waiting period rather than the usual 12 months. If we switched to one of these funds and upgraded our cover, could we get her knees done after the six months? The alternative is to upgrade the cover with our fund and wait for another year. Are there any traps? Bill

The wisdom: That’s a tough spot to be in after so many years with the same fund, says Tim Bennett, an insurance expert at comparison website Finder.