Been in 3 schools since this started and realise every school implements it differently. Every new P that comes also changes things. How is yours like? Mine is,

First school ; can only be used to extend your MC if you are still not feeling well. E.g., doc gave you 2 days, you still having symptoms, you use it to extend a 3rd day - but you need to inform P earlier. I've no idea how this works - it's like I can predict that I'm going to still be ill on the 3rd day? Never saw it work for anyone when I was there.

Same school ; another P. You can only use it for medical appointment that won't give you MC. Means, you must have had an urgent medical need, and an appointment that you die die cannot change, yet is also a medical appointment that won't give you an MC. So you tell P about it, and only after P approve, then you can confirm that medical appointment and use that leave. As usual, never saw it work in real life.

Second school ; Never heard it being used. P say - you follow HR policy. Yet, everyone that I knew that wanted to apply according to HR policy never got it. All got 'warned' not to abuse it.

Third school ; You use it, until you see the doctor that day and update it to be an actual MC. If you aren't sick enough to actually get an actual MC, you better get ready to explain.

Is this how this is supposed to be? Or I just have trash luck with schools and Ps? Checking because I have a chronic illness, not visible, and I really will like to use it but simply never got a chance too - have been dragging myself sick to work, and it's damaging to my health, making my chronic illness worse.