But - I am in my 40s and can remember when it was almost expected that you had a week off sick every year (have always worked in public sector)
Well that's odd, because I'm in my 50s, and have worked nigh on 30 years in the public sector and have never come across that attitude.
In answer to the original question - it depends on the illness, it depends on the work you do, it depends on what happens to that work if you are not in, it depends if you can stay at home and pick up some of the work from there, etc.,etc.,etc. There's no straight answer.