Personally, I have enough bills.
My contract at work gives a limited PHI - 26 weeks on full pay and 26 weeks on half pay. Any longer and I'd have to rely on state sick pay or disability.
A cheap alternative might be a term cover policy which ( in addition to life cover) pays a lumpsum on heart attacks, cancer and certain other illnesses. It's no good for bad backs and some chronic illnesses.
PHI policies might exclude depression and stress-related illnesses (sorry, i'm not sure about this!)